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ID-FRONTIERS for March 16-22, 2003
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Messages are displayed in the order they were received.
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| Subject | From | Date | Time |
| Franklin's Gull molt questions | Martin Reid | Sun, 16 Mar 2003 | 5:50am |
| Gull help requested (again) | Nick Komar | Sun, 16 Mar 2003 | 6:40am |
| Iceland/Thayer's Gull BNA | Jean Iron | Sun, 16 Mar 2003 | 10:20am |
| Re: Iceland/Thayer's Gull BNA | Phil Pickering | Sun, 16 Mar 2003 | 11:11am |
| Re: Franklin's Gull molt questions | Tony Leukering | Sun, 16 Mar 2003 | 11:53am |
| Re: Iceland/Thayer's Gull BNA | Alvaro Jaramillo | Sun, 16 Mar 2003 | 1:20pm |
| Re: Iceland/Thayer's Gull BNA | Millington/BIS | Sun, 16 Mar 2003 | 2:04pm |
| Spizella sparrow near Elma(photos) (fwd) | Ian Paulsen | Sun, 16 Mar 2003 | 5:04pm |
| Re: Iceland/Thayer's Gull BNA | Alvaro Jaramillo | Sun, 16 Mar 2003 | 6:10pm |
| Re: Iceland/Thayer's Gull BNA | Anthony L. Lang | Sun, 16 Mar 2003 | 7:37pm |
| "Kumlien's" x Thayer's 'intergrades' and IDing
glaucoides ICGUs | Michael Retter | Sun, 16 Mar 2003 | 9:42pm |
| Laughing x Ring-billed hybrid | Brian Boldt | Sun, 16 Mar 2003 | 10:18pm |
| Re: Iceland/Thayer's Gull BNA | Alain Foss=?ISO-8859 | Sun, 16 Mar 2003 | 10:34pm |
| Re: Laughing x Ring-billed hybrid | Alan Wormington | Mon, 17 Mar 2003 | 11:04am |
| Varied Thrush Puzzle | Angus Wilson | Mon, 17 Mar 2003 | 10:32pm |
| Ageing & Sexing Varied thrushes | Julian Hough | Tue, 18 Mar 2003 | 9:53am |
| Re: Varied Thrush Puzzle | Angus Wilson | Tue, 18 Mar 2003 | 9:55am |
| Re: Varied Thrush Puzzle | Julian Hough | Tue, 18 Mar 2003 | 11:15am |
| Re: Varied Thrush Puzzle | Tony Leukering | Tue, 18 Mar 2003 | 11:17am |
| Re: Varied Thrush Puzzle | Les Chibana | Tue, 18 Mar 2003 | 2:00pm |
| Re: Varied Thrush Puzzle | Mike Patterson | Tue, 18 Mar 2003 | 3:38pm |
| Re: Varied Thrush Puzzle | Angus Wilson | Tue, 18 Mar 2003 | 7:46pm |
| VA Beach Gull | John Puschock | Tue, 18 Mar 2003 | 9:28pm |
| Identification of Brant - Variability and
hybridization | Angus Wilson | Tue, 18 Mar 2003 | 11:37pm |
| Re: Varied Thrush Puzzle | Nathan Hentze | Wed, 19 Mar 2003 | 12:31am |
| Re: VA Beach Gull | Nick Rossiter | Wed, 19 Mar 2003 | 7:51am |
| Plumage variation in Varied Thrush | Julian Hough | Wed, 19 Mar 2003 | 10:27am |
| Re: Plumage variation in Varied Thrush | Matt Kenne | Wed, 19 Mar 2003 | 11:35am |
| Re: Winter Laughing Gulls | Ian Mclaren | Wed, 19 Mar 2003 | 12:45pm |
| Re: Varied Thrush Puzzle | Tony Leukering | Wed, 19 Mar 2003 | 4:15pm |
| Re: Winter Laughing Gulls | Tony Leukering | Wed, 19 Mar 2003 | 4:22pm |
| Re: Winter Laughing Gulls | Matt Kenne | Wed, 19 Mar 2003 | 7:28pm |
| Re: VA Beach Gull | Martin Reid | Thu, 20 Mar 2003 | 5:05am |
| RE : VA Beach Gull | =?iso-8859-1?Q?Pierr | Thu, 20 Mar 2003 | 6:52am |
| Re: Winter Laughing Gulls | D. Heindel | Thu, 20 Mar 2003 | 8:24am |
| Re: Winter Laughing Gull | Ian Mclaren | Thu, 20 Mar 2003 | 8:41am |
| Re: Winter Laughing Gull | Alvaro Jaramillo | Thu, 20 Mar 2003 | 9:42am |
| Winter LAGU | Gavin Bieber | Thu, 20 Mar 2003 | 10:01am |
| Re: VA Beach Gull | Peter Adriaens | Thu, 20 Mar 2003 | 10:50am |
| VA Beach Gull | Nick Rossiter | Thu, 20 Mar 2003 | 1:24pm |
| Re: Winter Laughing Gull | Floyd Hayes | Thu, 20 Mar 2003 | 2:10pm |
| Fwd: Re: Winter Laughing Gull | Alvaro Jaramillo | Fri, 21 Mar 2003 | 12:07am |
| RE : VA Beach Gull | =?iso-8859-1?Q?Pierr | Fri, 21 Mar 2003 | 2:47am |
|
To use email addresses replace '(AT)' with '@'.
This is done to confuse the spam 'bots.
|
[ << | >> | ^^ ]
Subject: Franklin's Gull molt questions
From: Martin Reid <upupa(AT)AIRMAIL.NET>
Date: 16 Mar 2003 5:50am
Dear all,
Can anyone point me to published works that discuss in detail the molt of
Franklin's Gull? My limited library contains few details beyond the idea
(from Grant's GULLS) that FRGUs undergoes a complete pre-migration molt in
the Spring and Fall (except for the partial first prebasic molt.) This is
repeated in Sibley's Field Guide, but I do not have any other references
that go into more detail.
I ask because I recently noticed that some of the FRGUs arriving just now
in Fort Worth, Texas seem to have two generations of primaries; see these
examples:
http://www.martinreid.com/frgu03.html
- is this an aberrant suspension of molt, or a normal partial molt? (and if
the latter, is it a hallmark of a particular age?)
Also FYI here's an adult FRGU that completely lacked white eye crescents:
http://www.martinreid.com/frgu02.html
Good Birding,
Martin Reid
Fort Worth, Texas
mailto:upupa(AT)airmail.net
http://www.martinreid.com
[ << | >> | ^^ ]
Subject: Gull help requested (again)
From: Nick Komar <quetzal65(AT)ATTBI.COM>
Date: 16 Mar 2003 6:40am
My apologies to the list for supplying a hyperlink that was non-functional.
This one should work: http://www.birdinghawaii.co.uk/WELCOMEPAGE.htm. Click
on the link for News, Events and Announcements, and then click on the gull
photo to see the series of photos of this interesting gull in Oahu.
Nick Komar
Fort Collins CO
----- Original Message -----
From: "Nick Komar" <quetzal65(AT)attbi.com>
To: <BIRDWG01(AT)listserv.arizona.edu>
Cc: "Peter Donaldson" <PDonaldson(AT)hawaii.rr.com>; "birding hawaii"
<birdinghawaii(AT)yahoo.com>
Sent: Saturday, March 08, 2003 5:44 PM
Subject: Gull help requested
> Photos of a first-basic gull that I saw in February in Oahu (Hawaii) are
> posted at
>
http://photos.groups.yahoo.com/group/hawaiibirding/vwp?.dir=/2003+Photograph
>
s&.src=gr&.dnm=Komar+Gull+1.jpg&.view=t&.done=http%3a//photos.groups.yahoo.c
>
om/group/hawaiibirding/lst%3f%26.dir=/2003%2bPhotographs%26.src=gr%26.view=t
> (clicking on this link brings up the first of three photos).
>
> I suspect "Vega" Gull (Larus argenteus vegae) because of the bright white
> rump in constrast with a dark mantle. I have no experience with this
> species. Can a Vega Gull expert comment on whether other features support
> the identification? Vega Gull is extrememly rare in Oahu (possibly never
> reported).
>
> I'd be interested in opinions as to the identity of this gull. Thanks.
>
> Nick Komar
> Fort Collins CO
>
>
>
>
>
>
>
[ << | >> | ^^ ]
Subject: Iceland/Thayer's Gull BNA
From: Jean Iron <jeaniron(AT)SYMPATICO.CA>
Date: 16 Mar 2003 10:20am
Account number 699 of the Iceland Gull (nominate glaucoides and kumlieni)
and Thayer's Gull (monotypic) in The Birds of North America by Richard
Snell arrived last week. There is much new data from Snell's original field
work and his examination of adult Iceland and Thayer's Gull specimens
collected from throughout the breeding range. Here are some highlights in
"quotes" and my comments.
1. Introduction: Snell says on page 2 "My studies, heretofore unpublished,
are suggestive of continuous phenotypic variation from darkest to lightest
extremes in plumage of adults across the breeding range. Where breeding
ranges of kumlieni and thayeri overlap (e. Baffin I., Southampton I.,
Digges Sound), there is no evidence of assortative mating: gulls as dark or
darker than the type of thayeri bred with others much lighter than the type
of kumlieni, including birds lacking visible wing-tip melanism. Based on
this, I believe only 1 species should be recognized with all taxa placed
under Iceland Gull."
2. Thayer's Gull: On page 3, "least melanistic thayeri, including some
specimens from Eureka, Ellesmere I., are lighter than dark kumlieni." There
is no information where these pale-winged thayeri from Ellesmere spend the
winter. "Iris color highly variable, including in western part of breeding
range of thayeri..." It is now generally agreed that eye color is extremely
variable from dark to clear yellow in both thayeri and kumlieni, but
averages darker in thayeri. On page 9, the character on which thayeri is
most distinct is mantle melanism, though there is broad overlap with
kumlieni."
3. Kumlien's Gull: On page 8, "Melanism of irides variable, extent of
speckling in irides variable; and no evidence of significant correlation
between melanism of irides and patterns on primary-feathers of adults on e.
Baffin I...Wing-tips of breeding adults range from patternless to
relatively restricted patterns shaded gray to dark gray with partial white
apical spots (Table 1). On average, mantles and P10 webs darker gray than
nominate glaucoides, but there is overlap between subspecies. Plumage and
mensural characters of kumlieni overlap both nominate glaucoides and
thayeri." Table 1 on page 9 referred to above shows the supporting data
from 7 geographic regions across the breeding range of the three taxa from
Greenland to Banks and Finlayson Islands in Canada. Figure 6 on page 6 is a
map showing the 7 regions used in this account and shows the locations of
the type specimens of kumlieni and thayeri. The type specimen of glaucoides
was from Iceland, but is not extant.
4. Nominate Iceland Gull: On page 8, "Although most sw. and e. Greenlandic
adults (i.e., well south of Thule region) lack wing-tip melanism, many
nominate glaucoides possess gray wing-tips and light patterning on
primary-feathers...Two e. Greenlandic chicks captured Jul 1964, and reared
in captivity, had markings on inner and outer webs of P10 when fully
adult...if viewed in the south as winter migrants, these birds would
doubtless be considered kumlieni. Near Nuuk, sw. Greenland, birds with
patterned wing-tips were relatively numerous in 2001: one was documented on
a nest 16 Jun...On average, male and female glaucoides have the smallest
tarsi and culmens, but there is overlap in mensural characters with
kumlieni." On page 12, "Most adults wintering in Iceland have traces of
melanism on one or more primaries." The above suggests introgression with
kumlieni.
5. Figure 3 on page 10: This illustration by David Beadle shows the range
of variation in 18 wing-tip patterns of thayeri, kumlieni and glaucoides
collected in the breeding range of Canada and Greenland. The illustration
includes the type specimens of thayeri and kumlieni. I believe that the
wing-tip drawing of the type specimen of Thayer's is not what most people
would call a typical Thayer's in the field, especially on the west coast.
The first drawing shows a dark thayeri wing-tip with a mirror on only P10
that is essentially the same as many NA Herring Gulls. Note that Snell does
not suggest that Thayer's should be merged with Herring Gull. This dark
extreme shows that wing-tip pattern and melanism varies in different
directions in thayeri. Snell states on page 9, "The type specimens for
kumlieni and thayeri may represent points in the clinal continua of
glaucoides, kumlieni, and thayeri rather than exemplars of discrete taxa..."
You can buy a copy of Snell's account of Iceland and Thayer's in The Birds
of North America, number 699, from Buteo Books
http://www.buteobooks.com/bna.html
I look forward to the ongoing discussions of these fascinating gulls.
Ron Pittaway
Minden and Toronto, Ontario
E-mail: jeaniron(AT)sympatico.ca
Jean Iron
President
Ontario Field Ornithologists
9 Lichen Place
Toronto ON M3A 1X3
416-445-9297
e-mail: jeaniron(AT)sympatico.ca
www.ofo.ca
[ << | >> | ^^ ]
Subject: Re: Iceland/Thayer's Gull BNA
From: Phil Pickering <philliplc(AT)HARBORSIDE.COM>
Date: 16 Mar 2003 11:11am
Recognizing kumlieni as an intergrade is one thing, but (asking in
ignorance of any genetic studies that have been done) does clinal
variation and interbreeding automatically make nominate glaucoides
and thayeri one species? How does this situation differ from
Western and Glaucous-winged, other than that introgression
is (perhaps) geographicaly more progressed?
Cheers,
Phil
> 1. Introduction: Snell says on page 2 "My studies, heretofore unpublished,
> are suggestive of continuous phenotypic variation from darkest to lightest
> extremes in plumage of adults across the breeding range. Where breeding
> ranges of kumlieni and thayeri overlap (e. Baffin I., Southampton I.,
> Digges Sound), there is no evidence of assortative mating: gulls as dark
or
> darker than the type of thayeri bred with others much lighter than the
type
> of kumlieni, including birds lacking visible wing-tip melanism. Based on
> this, I believe only 1 species should be recognized with all taxa placed
> under Iceland Gull."
[ << | >> | ^^ ]
Subject: Re: Franklin's Gull molt questions
From: Tony Leukering <GreatGrayOwl(AT)AOL.COM>
Date: 16 Mar 2003 11:53am
----INCLUDING text/plain MIME SECTION----
Hi all:
John Vanderpoel and I, while John was preparing his Small Gulls ID video,
noted that most of the Franklin's Gulls (FRGU) in Alternate I that he had
video of showed a similar pattern of primary retention to that of many
buteos, specifically that they retained a few of the outermost juvenal
primaries. John and I discussed it at length, but, unfortunately, he did not
have enough examples to make any sweeping statements so, I believe, left that
factoid out of the video.
Now, we did not note any such pattern in adults, so....
Sincerely,
Tony Leukering
Brighton, CO
----DELETED text/html MIME SECTION----
[ << | >> | ^^ ]
Subject: Re: Iceland/Thayer's Gull BNA
From: Alvaro Jaramillo <chucao(AT)ATTBI.COM>
Date: 16 Mar 2003 1:20pm
At 10:17 AM 3/16/2003 -0800, Phil Pickering wrote:
>Recognizing kumlieni as an intergrade is one thing, but (asking in
>ignorance of any genetic studies that have been done) does clinal
>variation and interbreeding automatically make nominate glaucoides
>and thayeri one species? How does this situation differ from
>Western and Glaucous-winged, other than that introgression
>is (perhaps) geographicaly more progressed?
>
>Cheers,
>
>Phil
Phil,
This doesn't answer your question, but interbreeding (hybridization)
and clinal variation are two different situations. In most cases a cline
occurs over a substantial geographic area, and change over that area is
gradual. Most geographic variation in Red-winged Blackbirds and Savannah
Sparrows (to give examples of species that have been studied extensively)
is clinal. These clines make it impossible for one to separate most
populations as discrete entities from each other. So most named subspecies
of both of these species are not workable as they are specific points on a
cline rather than distinct populations that differ diagonsably from the
next population over. The typical cline occurs within a species. When you
have a hybrid zone (such as in Western/Glaucous-winged gulls) the variation
can be termed a "step cline" since you have two levels (the parent species)
and a narrow area where the two are intermediate (the step). But these are
not clines in the way that one traditionally thinks of a cline:
Classical cline - from state A to state B:
---------------------------
B
-----------------------------
---------------------------
A -----------
Step cline (hybrid zone) from state A to state B
-------------------------------------------------------
B
--
---
---
A -----------------------------
The x-axis is geographical distance, y axis some morphological feature, or
composite of morphology.
In a very simplistic way to look at complex problems, if two "types" or
"taxa" exhibit a clear cline in morphology such as the top example, then it
suggests that the two are not separate. They are not on evolutionary
distinct trajectories, they in fact are part of the same thing. More than
likely these two should be treated as the same species. If differentiation
between populations A and B are not possible due to the completeness of the
cline, then you can't even give them separate subspecies status. Now if
genetic work shows that A and B are not each other's closest relatives and
they are behaving in this manner, that is a problem. The answers on what to
do with it are more muddy. It is clear now that species don't always just
arrive and remain, but they may be 'swallowed' up by hybridizing with
another species, or perhaps a new species could even arise from a hybrid
population, or at least a population that has genes it incorporated from
historical hybridization. Biologists refer to this generally as
'reticulation', and the true pattern of divergence in many species may be
much more like a reticulated web, than the nice little branching trees we
always picture.
In the hybrid zone, or step cline example (the bottom one) the two taxa may
very well be different species. They are retaining their overal
morphological (and genetic) differences, but only in a limited part of
their range are they mixed up in this hybrid situation. If the two forms
are not each other's closest relatives (sister species) then it makes sense
to retain them as separate species, otherwise your phylogeny of the group
becomes muddled with species that do not properly reflect the history of
the group. Available evidence, mainly genetic, has shown that Western Gull
and Glaucous-winged Gull are not sister species, the same goes for
Bullock's and Baltimore Orioles. Its tougher to decided what to do when the
two taxa are sisters, such as in Myrtle and Audubon's Warbler which show a
step cline in morphology in the limited area where they hybridize. Some
sister taxa in this situation are considered separate species such as
Townsend's Warblers and Hermit Warblers, but not in others such as the
Yellow-rumped Warbler example. Some of this difference is just due to
inconsistencies in treatment by taxonomic bodies as understanding of
speciation and new techniques that allow one to look at gene flow and
genetic differentiation have evolved. Some of it is also due to what is
published and known, versus yet unknown. Factors that need to be considered
are what are the levels of gene flow between the populations, are the
clines stable?, does the genetic data suggest that the two taxa have been
separate for a long period of time (genetic distances between populations),
etc.
But to get back to the Thayer's x Iceland situation, I think that part of
what is happening is that it is unclear which one of these two patterns the
group falls into. Richard Snell has data that is strongly suggestive that
it is the clinal pattern. Clines in the Arctic Islands are really difficult
to deal with however. If you look at the geography of the place there is a
large north-south gradient as well as east-west gradient where things can
happen, and the pattern of variation in this complex seems to differ
depending on where you are in the Arctic. Thayer's are not just west of
'kumlien's', they are also north of them. If you look at a globe and look
at the Arctic from above, there are probably breeding areas of Thayer's
that are closer geographically to nominate Iceland than they are to
Kumlien's (would need to pull the globe myself and figure out if this is
the case, but it is certainly not unlikely). Apart from the messy
geography, these are also islands and islands function in their own
peculiar manner. So who knows, there may be classic clines within taxa
here, as well as hybrid zones. I think two things have to happen before any
of this can be resolved. First of all, the data set on geographic variation
in morphology of this group needs to be published and assessed. Also we
need to clarify if Thayer's and Iceland are sister taxa or not, and I
recall that the latest gull work by Trochet suggest they are not. Steve
Howell and Bruce Mctavish's recent paper in Alula is interesting in that it
shows that most adult Kumlien's are separable from most Thayer's based on
field studies of large numbers of each on the wintering grounds. In other
words, there is little overlap in plumage pattern between the two, although
the differences are subtle. I think they make a good argument that this is
the case. What is also true, looking at their data, is that Kumlien's Gull
is rather variable. When you think about this, its odd. Sure there is a lot
of variability in gulls, particularly when they are young, but as adults
the variability shown by most taxa is not nearly as much as that shown by
Kumlien's Gull. Why is it so variable? There has to be a reason. The
suggestion that Kumlien's is of hybrid origin between Thayer's and Iceland
fits neatly as an answer to this. Perhaps its not all that dissimilar from
the Western and Glaucous-winged Gull situation in this respect. Imagine
that "Olympic Gull" or "Puget Sound Gull" had been described as a different
entity, and we believed it was a different entity. It would make our
understanding of the relationships between Western and Glaucous-winged Gull
a lot less clear.
cheers
Alvaro
Alvaro Jaramillo
Biologist
San Francisco Bay Bird Observatory
P.O. Box 247
Alviso, CA 95002
(408)-946-6548
http://www.sfbbo.org/
chucao(AT)attbi.com
[ << | >> | ^^ ]
Subject: Re: Iceland/Thayer's Gull BNA
From: Millington/BIS <sales(AT)BIRDINGWORLD.CO.UK>
Date: 16 Mar 2003 2:04pm
Hi
Alvaro's comments are most lucid and very helpful.
The recent Alula article goes one or two steps further than Alvaro mentions,
and suggests that Kumlien's Gull, although variable, is c95% diagnosable and
may possibly merit species status.
Furthermore, there is the suggestion that 'pale-winged' Thayer's may result
from thayeri and glaucoides occasionally hybridising to the north of
kumlieni (hypothetically)
Certainly, there seems a very solid case for thayeri and glaucoides being
diagnosable units (species), with kumlieni (possibly consisting of two
forms, say the authors....) being either a hybrid swarm or a recognisable
taxon.
The evidence for this is substantial, as a high proportion of each form that
can be seen in the wintering areas where, as with some other gulls (& brent
geese and many ducks etc), the appearance and variation of the majority of
birds is far easier to assess than on the breeding grounds.
If the situation is clinal as Snell states, where do all the (thousands of?)
confusing 'intergrades' winter? Currently they remain just hypothetical
entities
cheers
Richard
sales(AT)birdingworld.co.uk
(Birding World, Books for Birders & Birdline)
Bird Information Service, Stonerunner, Coast Road,
Cley next the Sea, Holt, Norfolk, NR25 7RZ, UK
Tel. 44 (0) 1263 741139 Fax. 741173
Website www.birdingworld.co.uk
-----Original Message-----
From: Alvaro Jaramillo <chucao(AT)ATTBI.COM>
To: <BIRDWG01(AT)listserv.arizona.edu>
Date: 16 March 2003 20:25
Subject: Re: [BIRDWG01] Iceland/Thayer's Gull BNA
>At 10:17 AM 3/16/2003 -0800, Phil Pickering wrote:
>>Recognizing kumlieni as an intergrade is one thing, but (asking in
>>ignorance of any genetic studies that have been done) does clinal
>>variation and interbreeding automatically make nominate glaucoides
>>and thayeri one species? How does this situation differ from
>>Western and Glaucous-winged, other than that introgression
>>is (perhaps) geographicaly more progressed?
>>
>>Cheers,
>>
>>Phil
>
>Phil,
>
> This doesn't answer your question, but interbreeding (hybridization)
>and clinal variation are two different situations. In most cases a cline
>occurs over a substantial geographic area, and change over that area is
>gradual. Most geographic variation in Red-winged Blackbirds and Savannah
>Sparrows (to give examples of species that have been studied extensively)
>is clinal. These clines make it impossible for one to separate most
>populations as discrete entities from each other. So most named subspecies
>of both of these species are not workable as they are specific points on a
>cline rather than distinct populations that differ diagonsably from the
>next population over. The typical cline occurs within a species. When you
>have a hybrid zone (such as in Western/Glaucous-winged gulls) the variation
>can be termed a "step cline" since you have two levels (the parent species)
>and a narrow area where the two are intermediate (the step). But these are
>not clines in the way that one traditionally thinks of a cline:
>
>Classical cline - from state A to state B:
>
> ---------
------------------
>B
> -----------------------------
> ---------------------------
>A -----------
>
>Step cline (hybrid zone) from state A to state B
> -------------------------------------
------------------
>B
> --
> ---
> ---
>A -----------------------------
>
>The x-axis is geographical distance, y axis some morphological feature, or
>composite of morphology.
>
>In a very simplistic way to look at complex problems, if two "types" or
>"taxa" exhibit a clear cline in morphology such as the top example, then it
>suggests that the two are not separate. They are not on evolutionary
>distinct trajectories, they in fact are part of the same thing. More than
>likely these two should be treated as the same species. If differentiation
>between populations A and B are not possible due to the completeness of the
>cline, then you can't even give them separate subspecies status. Now if
>genetic work shows that A and B are not each other's closest relatives and
>they are behaving in this manner, that is a problem. The answers on what to
>do with it are more muddy. It is clear now that species don't always just
>arrive and remain, but they may be 'swallowed' up by hybridizing with
>another species, or perhaps a new species could even arise from a hybrid
>population, or at least a population that has genes it incorporated from
>historical hybridization. Biologists refer to this generally as
>'reticulation', and the true pattern of divergence in many species may be
>much more like a reticulated web, than the nice little branching trees we
>always picture.
>
>In the hybrid zone, or step cline example (the bottom one) the two taxa may
>very well be different species. They are retaining their overal
>morphological (and genetic) differences, but only in a limited part of
>their range are they mixed up in this hybrid situation. If the two forms
>are not each other's closest relatives (sister species) then it makes sense
>to retain them as separate species, otherwise your phylogeny of the group
>becomes muddled with species that do not properly reflect the history of
>the group. Available evidence, mainly genetic, has shown that Western Gull
>and Glaucous-winged Gull are not sister species, the same goes for
>Bullock's and Baltimore Orioles. Its tougher to decided what to do when the
>two taxa are sisters, such as in Myrtle and Audubon's Warbler which show a
>step cline in morphology in the limited area where they hybridize. Some
>sister taxa in this situation are considered separate species such as
>Townsend's Warblers and Hermit Warblers, but not in others such as the
>Yellow-rumped Warbler example. Some of this difference is just due to
>inconsistencies in treatment by taxonomic bodies as understanding of
>speciation and new techniques that allow one to look at gene flow and
>genetic differentiation have evolved. Some of it is also due to what is
>published and known, versus yet unknown. Factors that need to be considered
>are what are the levels of gene flow between the populations, are the
>clines stable?, does the genetic data suggest that the two taxa have been
>separate for a long period of time (genetic distances between populations),
>etc.
>
>But to get back to the Thayer's x Iceland situation, I think that part of
>what is happening is that it is unclear which one of these two patterns the
>group falls into. Richard Snell has data that is strongly suggestive that
>it is the clinal pattern. Clines in the Arctic Islands are really difficult
>to deal with however. If you look at the geography of the place there is a
>large north-south gradient as well as east-west gradient where things can
>happen, and the pattern of variation in this complex seems to differ
>depending on where you are in the Arctic. Thayer's are not just west of
>'kumlien's', they are also north of them. If you look at a globe and look
>at the Arctic from above, there are probably breeding areas of Thayer's
>that are closer geographically to nominate Iceland than they are to
>Kumlien's (would need to pull the globe myself and figure out if this is
>the case, but it is certainly not unlikely). Apart from the messy
>geography, these are also islands and islands function in their own
>peculiar manner. So who knows, there may be classic clines within taxa
>here, as well as hybrid zones. I think two things have to happen before any
>of this can be resolved. First of all, the data set on geographic variation
>in morphology of this group needs to be published and assessed. Also we
>need to clarify if Thayer's and Iceland are sister taxa or not, and I
>recall that the latest gull work by Trochet suggest they are not. Steve
>Howell and Bruce Mctavish's recent paper in Alula is interesting in that it
>shows that most adult Kumlien's are separable from most Thayer's based on
>field studies of large numbers of each on the wintering grounds. In other
>words, there is little overlap in plumage pattern between the two, although
>the differences are subtle. I think they make a good argument that this is
>the case. What is also true, looking at their data, is that Kumlien's Gull
>is rather variable. When you think about this, its odd. Sure there is a lot
>of variability in gulls, particularly when they are young, but as adults
>the variability shown by most taxa is not nearly as much as that shown by
>Kumlien's Gull. Why is it so variable? There has to be a reason. The
>suggestion that Kumlien's is of hybrid origin between Thayer's and Iceland
>fits neatly as an answer to this. Perhaps its not all that dissimilar from
>the Western and Glaucous-winged Gull situation in this respect. Imagine
>that "Olympic Gull" or "Puget Sound Gull" had been described as a different
>entity, and we believed it was a different entity. It would make our
>understanding of the relationships between Western and Glaucous-winged Gull
>a lot less clear.
>
>cheers
>
>Alvaro
>
>Alvaro Jaramillo
>Biologist
>San Francisco Bay Bird Observatory
>P.O. Box 247
>Alviso, CA 95002
>(408)-946-6548
>http://www.sfbbo.org/
>chucao(AT)attbi.com
[ << | >> | ^^ ]
Subject: Spizella sparrow near Elma(photos) (fwd)
From: Ian Paulsen <ipaulsen(AT)KRL.ORG>
Date: 16 Mar 2003 5:04pm
HI:
Any comments?
Ian Paulsen
Bainbridge Island, WA, USA
ipaulsen(AT)krl.org
A.K.A.: "Birdbooker"
"Rallidae all the way"
---------- Forwarded message ----------
Date: Sun, 16 Mar 2003 14:45:21 -0800
From: Ruth Sullivan <GODWIT(AT)worldnet.att.net>
To: tweeters(AT)u.washington.edu
Subject: Spizella sparrow near Elma(photos)
Hello Tweets,
My mother and I have placed 4 photos of the unidentified Spizella sparrow that
we observed yesterday near Elma,hoping we may get some feedback on the possible
identity of the bird between either an abbarent Clay-colored Sparrow or a hybrid
between a Chipping and Clay-colored Sparrow. We have placed the 4 photos at our
yahoo site at: http://photos.yahoo.com/godwit2003/. The photos labeled
sparrow1-3 were taken by mother at very close range and are of the best quality
and the photo labeled sparrow4 was taken by me(Patrick) and is of less
quality,but perhaps we may still get some feedback from anyone that may give us
an opinion in open or privately. Nevertheless,it is a very intersting
sparrow,even if it turns out to be a hybrid.
Thank you for any assistance,
Ruth and Patrick Sullivan
godwit(AT)worldnet.att.net
[ << | >> | ^^ ]
Subject: Re: Iceland/Thayer's Gull BNA
From: Alvaro Jaramillo <chucao(AT)ATTBI.COM>
Date: 16 Mar 2003 6:10pm
At 09:01 PM 3/16/2003 +0000, Millington/BIS wrote:
>Hi
>
>The recent Alula article goes one or two steps further than Alvaro mentions,
>and suggests that Kumlien's Gull, although variable, is c95% diagnosable and
>may possibly merit species status.
>
>Certainly, there seems a very solid case for thayeri and glaucoides being
>diagnosable units (species), with kumlieni (possibly consisting of two
>forms, say the authors....) being either a hybrid swarm or a recognisable
>taxon.
Thanks to Richard for giving us a more detailed summary of the Alula
article, which is worth a read. In fact all three of Steve Howell's (and
collaborators) Alula papers (or was it more?) in the last few years are
definitely worth a read.
I think that while according to the latest paper there is a low degree
of overlap between thayeri and kumlieni based on the features they looked
at, this does not necessarily mean there is not a large area of
interbreeding, and as Richard's last sentence notes the possibility that
this is a hybrid swarm is still there. So while the paper clarifies how to
diagnose (ID) the two entities, it gets us no closer to answering the
question of how many species are involved here. It also depends on what
flavour of species you are most attached to. The high degree of variability
within Kumlien's still needs to be explained.
>The evidence for this is substantial, as a high proportion of each form that
>can be seen in the wintering areas where, as with some other gulls (& brent
>geese and many ducks etc), the appearance and variation of the majority of
>birds is far easier to assess than on the breeding grounds.
Yes and no, but I agree with the overall point that Richard (and the Alula
paper makes). The information gathered from wintering birds is extremely
useful. It would have been next to impossible to sample this many birds in
the breeding range so quickly and so cheaply. However the same information
from the breeding grounds would be much more meaningful and could get to
the crux of the problem of how many species are involved, by looking at
wintering populations you can't do this without making a great number of
assumptions, which could be wrong. Only one wintering area for kumlien's
was looked at, is it representative of all of the east coast? How would it
compare to the Great Lakes?
>If the situation is clinal as Snell states, where do all the (thousands of?)
>confusing 'intergrades' winter? Currently they remain just hypothetical
>entities
I bet Great Lakes and St. Lawrence River birds are a bit different, but
there sample sizes will be much lower.
My guess is that some birds that are considered intergrades by Snell would
be considered within the range of variation in kumlien's by Howell and
McTavish. How you interpret these intergrade plumages depends on the
context, its different when you can see what else is present at the
breeding colony for example. Also how you define diagnosibility depends on
what you were measuring, and how you analysed these measurements. Howell
and McTavish set up their data to be looked at graphically, but there is no
statistical test shown that gives you data on the confidence one can have
on the diagnosability of these taxa. Basically, how much slop does the data
have? What are the confidence limits of the numbers? We don't know. The
graphical representation lacks a sample size for Iceland Gulls, was one or
a 1000 birds measured? This has bearing on how you interpret the data. They
plot proportions against estimated Kodak Values of wingtip darkness, but
these are averaged estimates (scores of 7-10, become an 8.5 on the plot).
This averaging can lead to a cleaner looking data set than what was really
there, and it makes me wonder why they didn't just plot the wingtip scores
rather than convert them to kodak values. Finally, and I get back to this
variability within Kumlien's, the pattern of the data is important. You
have two end points (Iceland and Thayer's) which clearly differ from each
other, and show low (non-existent in Iceland here, but no sample size
given) amounts of variation within each taxon. Then the intermediate taxon
is much more variable than either end point taxon, and at least some
individuals overlap with each end point taxon. This is exactly the pattern
that you would expect in a hybrid swarm, and exactly the pattern that you
would not expect if these were three nice little species going along their
own business.
Please don't interpret this as a dismissal of what Howell and
McTavish have found. Their data is extremely useful, its well worth reading
(necessary for any gull aficionado and gull researcher) and they make some
solid arguments here. Its great work, and like any good bit of work it asks
more questions than it answers.
regards
Alvaro Jaramillo
Biologist
San Francisco Bay Bird Observatory
P.O. Box 247
Alviso, CA 95002
(408)-946-6548
http://www.sfbbo.org/
chucao(AT)attbi.com
[ << | >> | ^^ ]
Subject: Re: Iceland/Thayer's Gull BNA
From: "Anthony L. Lang" <tlang(AT)ROGERS.COM>
Date: 16 Mar 2003 7:37pm
----- Original Message -----
From: "Millington/BIS" <sales(AT)BIRDINGWORLD.CO.UK>
To: <BIRDWG01(AT)listserv.arizona.edu>
Sent: Sunday, March 16, 2003 4:01 PM
Subject: Re: [BIRDWG01] Iceland/Thayer's Gull BNA
> If the situation is clinal as Snell states, where do all the (thousands
of?)
> confusing 'intergrades' winter? Currently they remain just hypothetical
> entities
In my experience here around Lake Ontario, the wingtip patterns of putative
_kumlieni_ adults (as viewed in flight) are very variable. Perhaps we have
the whole range of variation from _thayeri_ through _kumlieni_ to
_glaucoides_ right here. There are certainly a few well-documented
_thayeri_ known from our area. Now if those Thayer's/Iceland birds would
hold still long enough we could have a good look at them and document this
variation. However, this variation doesn't tell us much unless we know
where each one hatched.
Regarding whether classical clinal variation makes _thayer_ and _kumlieni_
one species, in such a case we couldn't separate the birds into diagnosable
groups so we would be forced to treat them all as one species (both
phylogenetic species and biological species). However, we wouldn't be able
to tell whether the cline arose because of hybridization after secondarily
coming into contact.
=======================================================
Anthony L. Lang
#22-6050 Bidwell Trail
Mississauga, Ontario, Canada
L5V 1V6
tel: 905-812-5513
tlang(AT)rogers.com
"Marshall McLuhan got it wrong. It isn't the medium that is the message.
It's the marketing." -- Rick Mercer
=======================================================
[ << | >> | ^^ ]
Subject: "Kumlien's" x Thayer's 'intergrades' and IDing
glaucoides ICGUs
From: Michael Retter <mretter(AT)HOTMAIL.COM>
Date: 16 Mar 2003 9:42pm
"If the situation is clinal as Snell states, where do all the (thousands
of?) confusing 'intergrades' winter? Currently they remain just hypothetical
entities."
I can't account for thousands, but I may be able to do so for dozens or even
hundreds. Ever since I have been looking at winter gulls here in Illinois,
I have been seeing birds I call Thayer's X "Kumlien's" intergrades.
First let's define Thayer's X "Kumlien's" intergrade. If Kumlien's is a
hybrid swarm between thayeri and glaucoides, then these so-called
intergrades are merely dark-end (more thayeri-like) hybrids ("backcrosses").
In this case the term doesn't really have much meaning. BUT, if kumlieni
is a good taxon (about which I have serious doubts), then 'Thayer's X
"Kumlien's" intergrade' would seem to be a good name for these birds which
seem too light for thayeri but too dark for kumlieni.
I see individuals that I call intergrades regularly in Illinois. For
example, here are my totals this winter from a few days of gulling, at
Starved Rock Lock and Dam, LaSalle Co, IL . . .
THAYER'S GULL
36+ (7+ 1w, 2 2w, 2 3w, 25+ ad.) 16 Feb.
12+ (3 1w, 1 3w, 1 4w, 7+ ad) 10 Feb.
4 (1w, 1 2w, 2 3w, 15+ ad) 11 Feb.
9+ (2 1w, 1 3w, 6+ ad) 8 Feb.
12+ (2 1w, 1 2w, 1 3w, 8+ ad) 28 Jan.
2 (2 ad) 25 Jan.
KUMLIEN'S GULL
3+ (3+ ad) 16 Feb.
3 (1 1w, 2 ad) 10 Feb.
5 (1 1w, 4 ad) 11 Feb.
4+ (1 1w, 1 2w, 2+ ad) 8 Feb.
2 (2 ad) 28 Jan.
3 (3 ad) 25 Jan.
INTERGRADES
3 (3 ad) Feb. MR.
5 (1 1w, 4 ad) 10 Feb.
6 (1 3w, 5 ad) 11 Feb.
2 (2 ad) 8 Feb.
2 (2 ad) 25 Jan.
This winter I saw just as many intergrades as I did "good" Kumlien's Gulls.
"Common knowledge" among Illinois birders seems to be that these birds are
out there and are not rare. I distinctly remember the first time I saw such
an individual. The bird, an adult, flew past, and I asked "was that a
Thayer's or an Iceland?" One of the most experienced observers in the state
at the time replied, "Good question. Those are the ones we try to forget we
saw." He went on to explain that he sees a few each season. Others there
agreed.
Unfortunately I can't say that others across the country and the globe would
not call what I term intergrades either light thayeri or dark kumlieni, or
both.
I was able to get pictures of one such bird on 25 Jan 2003, and 3 photos are
available for viewing at
http://photos.yahoo.com/bc/mlretter/lst?.dir=/other+Starved+Rock+gulls&.src=ph&.view=t
Marked "possible intergrade", all 3 photos are of the same bird.
Unfortunately, they are all shots of the bird at rest. When the wings were
spread they showed an almost perfect thayeri wing pattern, but the primary
tip markings were not black. They were a very dark slate gray. The
subterminal dark bars on P-8 and P-9 were thinner than I expect on thayeri,
but perhaps not out of the range of variation for that taxon. The mantle
was slightly lighter than those of the adjacent Herring Gulls. Its eye was
amber, not brown, and not yellow, for what that's worth.
Other individuals I have called intergrades are similar to this bird; some
are not. Some are like Kumlien's with (usually) dark mantles. They have
the restricted markings in the primaries like Kumlien's, but the markings
are jet black.
Someday I hope to know the true status and identification of these birds,
but until then, 'intergrade' is the best I can do. Perhaps that
desigination is right; perhaps it is not. Any comments would be greatly
appreciated.
Also at the same URL mentioned above, are 3 pics of a Iceland Gull that
looked like a glaucoides. From what we could tell, the wingtips were pure
white. The eye however, was amber, not yellow. Is this enough to eliminate
glaucoides? Again, any commentary is appreciated.
----------
Michael L. P. Retter
Bloomington, McLean Co, IL
mlretter(AT)yahoo.com
309.824.7317
see some of my drawings at: http://www.iwu.edu/~mretter/drawings.htm
>From: "Anthony L. Lang" <tlang(AT)ROGERS.COM>
>Reply-To: "Anthony L. Lang" <tlang(AT)ROGERS.COM>
>To: BIRDWG01(AT)listserv.arizona.edu
>Subject: Re: [BIRDWG01] Iceland/Thayer's Gull BNA
>Date: Sun, 16 Mar 2003 21:37:36 -0500
>
>----- Original Message -----
>From: "Millington/BIS" <sales(AT)BIRDINGWORLD.CO.UK>
>To: <BIRDWG01(AT)listserv.arizona.edu>
>Sent: Sunday, March 16, 2003 4:01 PM
>Subject: Re: [BIRDWG01] Iceland/Thayer's Gull BNA
>
>
> > If the situation is clinal as Snell states, where do all the (thousands
>of?)
> > confusing 'intergrades' winter? Currently they remain just hypothetical
> > entities
>
>In my experience here around Lake Ontario, the wingtip patterns of putative
>_kumlieni_ adults (as viewed in flight) are very variable. Perhaps we have
>the whole range of variation from _thayeri_ through _kumlieni_ to
>_glaucoides_ right here. There are certainly a few well-documented
>_thayeri_ known from our area. Now if those Thayer's/Iceland birds would
>hold still long enough we could have a good look at them and document this
>variation. However, this variation doesn't tell us much unless we know
>where each one hatched.
>
>Regarding whether classical clinal variation makes _thayer_ and _kumlieni_
>one species, in such a case we couldn't separate the birds into diagnosable
>groups so we would be forced to treat them all as one species (both
>phylogenetic species and biological species). However, we wouldn't be able
>to tell whether the cline arose because of hybridization after secondarily
>coming into contact.
>
>=======================================================
>Anthony L. Lang
>#22-6050 Bidwell Trail
>Mississauga, Ontario, Canada
>L5V 1V6
>tel: 905-812-5513
>tlang(AT)rogers.com
>
>"Marshall McLuhan got it wrong. It isn't the medium that is the message.
>It's the marketing." -- Rick Mercer
>=======================================================
_________________________________________________________________
STOP MORE SPAM with the new MSN 8 and get 2 months FREE*
http://join.msn.com/?page=features/junkmail
[ << | >> | ^^ ]
Subject: Laughing x Ring-billed hybrid
From: Brian Boldt <bboldt(AT)EXCELCOMM.COM>
Date: 16 Mar 2003 10:18pm
This is a multi-part message in MIME format.
----INCLUDING text/plain MIME SECTION----
I'm a new member to the list but have been following on Jack Siler's =
site for quite a while; I was prompted to finally join by the wonderful =
ongoing Thayer's/Kumlein's thread.
I found this bird today and thought I would post to the group as it =
makes a nice comparison to Martin Reid's Franklin's hybrid of a while =
ago:
http://birds.excelcomm.com/gullpage/hybrid.asp
Brian Boldt / Milwaukee, WI
----DELETED text/html MIME SECTION----
[ << | >> | ^^ ]
Subject: Re: Iceland/Thayer's Gull BNA
From: Alain Foss=?ISO-8859-1?B?6Q==?= Angers 49 F <alfosse(AT)WANADOO.FR>
Date: 16 Mar 2003 10:34pm
Le 17·3·03 2:09, Alvaro Jaramillo à chucao(AT)ATTBI.COM a écrit :
> So while the paper clarifies how to
> diagnose (ID) the two entities, it gets us no closer to answering the
> question of how many species are involved here.
In
YÉSOU P., 2002.
Trends in systematics. Systematics of Larus argentatus-cachinnans-fuscus
complex revisited.
Dutch Birding, 24 (5) : 271-298.
the author thinks kumlieni is a hybrid between the 2 species thayeri and
glaucoides.
Best regards.
•============================================•
Alain Fossé,LPO Anjou,Montreuil-Juigné,France
47° 31' 34" N, 0° 35' 43" W
<alfosse(AT)wanadoo.fr>
My digiscoping
<http:/www.digimages.info/>
My French List of the Birds of the World
<http://membres.lycos.fr/listoiseauxmonde/>
Web Site LPO Anjou<http://www.lpo-anjou.org/>
•============================================•
[ << | >> | ^^ ]
Subject: Re: Laughing x Ring-billed hybrid
From: Alan Wormington <wormington(AT)JUNO.COM>
Date: 17 Mar 2003 11:04am
Several years ago (around March 10th), I observed an adult Laughing X
Ring-billed Gull here at Point Pelee (Ontario). Does anyone know if a
compilation has been done on this hybrid type re occurrence dates and
locations? I can provide the exact details of my sighting, if someone is
interested.
Alan Wormington
Leamington, Ontario
[ << | >> | ^^ ]
Subject: Varied Thrush Puzzle
From: Angus Wilson <wilsoa02(AT)MED.NYU.EDU>
Date: 17 Mar 2003 10:32pm
Last night I posted two pictures of a Varied Thrush that was discovered by Al
Wollin at Hempstead Lake State Park on Long Island, New York on Saturday
afternoon and glimpsed by a small crowd of local birders the following morning.
Several correspondents have expressed surprise at my identification of this
bird as an adult female. The surprise comes from the fact that the bird was
heard singing (brief snatches) on several occasions.
http://www.oceanwanderers.com/NYVariedThrush.html
The identification as a female is based primarily on the absence of a strong
breast band. According to the few sources I can muster (Pyle 1997, Clement 2000
and George 2002), males always show a well-defined but not necessarily
complete, breast band. Looking carefully at the photos, which I admit are a
little over-exposed, there may be a hint of darker color across the breast.
However, this is far weaker than the literature would indicate for males
(hatching year or older) and for that matter, weaker than on many adult
females. Also supportive of a female are the pale orange tones of the under
parts, whitish belly and lower breast and the presence of some whitish patches
across the breast. I should add that most of the popular field guides were
pretty disappointing on this topic, most failing to explain, let alone
illustrate, how first year birds compare to adults.
In terms of aging, I feel much less confident. I wrote adult female on the web
page (grasping to explain the singing) but this might easily be incorrect.
Julian Hough has been thinking about this topic more carefully, in response to
a female that is present in Connecticut, and perhaps he can chime in for
himself. The relative degree of brown suffusing the dark gray areas on the
crown, mantle and upper-side of the tail are key, supplemented with detail of
molt and wear. Unfortunately, the very distant and 'from below' views of the
Long Island bird make these attributes difficult to assess.
So the big question is why is the bird singing? I haven't found any mention in
the literature to suggest that female Varied Thrushes sing on a regular basis.
If it does occur, one might expect it to be most common in older, more mature,
females (elevated testosterone levels?). Luke George mentions that both males
and females utter two types of call during aggressive encounters with other
birds. These are a 'vree' (with or without a trill) or a harsh 'churr' note.
These can be given in combination, perhaps sounding a bit like song? This is
probably NOT what was heard at Hempstead on Sunday but is as close as I can get
to a 'female song'.
Do west coast birders or museum collection managers know of proven males that
show a very weak breast band? Is there evidence for singing by female Varied
Thrushes, or other _Zoothera_ thrushes for that matter?
Useful Sources:
Clement, P. (2000) Thrushes. Princeton University Press.
George, T. L. (2002) Varied Thrush. No. 541. Birds of North America.
Pyle, P. (1997) Identification Guide to North American Birds. Part 1.
Many thanks to Dave Klauber, Andy Guthrie and Julian Hough for specific
information and stimulating discussion.
I look forward to enlightenment. Unless there is a specific reason, please post
to the whole group or let me know if you don't want your thoughts to be shared.
Cheers, Angus Wilson
New York City
http://www.oceanwanderers.com
-------------------------------------------------
This mail sent through IMP: http://horde.org/imp/
[ << | >> | ^^ ]
Subject: Ageing & Sexing Varied thrushes
From: Julian Hough <Jrhough1(AT)AOL.COM>
Date: 18 Mar 2003 9:53am
Based on my conversations with Angus Wilson re: the NY bird, here's my two
pennies worth based on recent CT individuals.
(see surfbirds NAmerican Rarities) There is not much precise info available in
the popular press, but I think that the best clue to ageing females is the
presence of brown tones to the crown, mantle and tail. In good light and close
views, these can be seen. The best indicator to look at in the field is a
brownish tail for first-winters and a bluish/grey tail for adult females (based
on Pyle et al). Also, a moult contrast in the greater coverts may aid ageing,
but I think the pattern of replaced feathers may be similar to
juv. outers making it difficult to discern differences in pattern between the
two generations of feathers.
I'd be interested to hear from banders whether this is accurate or not.
I think the orange on the underparts may be too variable for ageing (but i
don't know for sure).
It seems, from my limited field experience and examination of skins that males
and females were not too difficult to sex on breast band definition and colour.
Basically, first-winter males and adult males are very similar and probably
difficult to age in winter. (f-w with brownish tones to the tail and
primaries?). Basically, a bird with a blackish breastband, auriculars and dark
slate grey mantle should be a male.
A bird with pale greyish upperparts, greyish auriculars and breastband is a
female.
Regarding the NY bird, it looks like a female so maybe females do give a
sub-song??
If not, and this is a male then the literature has to be rewritten.
Julian Hough,
Graphic Designer,
Atlas Container Corp.
[ << | >> | ^^ ]
Subject: Re: Varied Thrush Puzzle
From: Angus Wilson <wilsoa02(AT)MED.NYU.EDU>
Date: 18 Mar 2003 9:55am
In response to my earlier posting, two regular contributors to ID-F from
California sent me their thoughts on the 'singing female' Varied Thrush
from Long Island, New York. Both make good points and I hope they don't
mind me sharing them with the whole group. Also Dave Klauber, a
co-observer of the bird in question, offered his impressions of the
vocalizations. I guess one possibility is that the bird is in fact a
male (hormonally at least) that for some reason has not developed the
appropriate plumage? Another theory, these plausible scenario would be a
second (male) Varied Thrush, singing from a grassy knoll just out of
sight. Perhaps Oliver Stone can comment on this :)
Cheers, Angus Wilson
*************************************
Looks like a female to me. I have both sexes wintering in the forest
around us this year (a good year for them, locally). The adult males are
a nice slate gray in the dark plumage. This bird looks like a Second
Year (SY) female from the indistinct breast band and brown dark
markings. A SY male would have a more definite breast band. The graphic
for this species account in Pyle shows that SY and After Second Year
(ASY) birds can be aged and sexed with a high degree of confidence in
March. I know nothing about the different races, which appear to be
differentiated in the female plumage and breeding range. It appears that
we could see all four in a central CA winter.
I am only aware of the "vree" song notes and the "tschook" call note.
The song often sounds half-hearted (less developed) through winter, and
gets more drawn out and buzzier when sung just before they depart from
the wintering areas and on the breeding grounds (like in Alaska). I
wonder if the females are capable of singing a less- developed song as
in the Carpodacus finches? I haven't found any references that say so,
however.
Les Chibana, Palo Alto CA
A couple of very quick thoughts. I have never seen any Varied Thrush
lacking a breast band, this is really an odd trait no matter what age or
sex you consider the bird to be. However, missing band more likely on
younger birds or female, I agree. Darkness of the face and the real
blue-grey tone to the back looks good for male. Have no data on singing
females in Varied Thrush, I have never seen a female American Robin
singing, that is the best I can do. If it was me, I would put the
singing behaviour as a clearer sign of sex than the plumage but that is
from biases I have. Looking at blackbirds vocal behaviour is very sex
dependent with certain vocalizations given by one sex and one sex only,
while in others it is variable. Most migratory, sexually dimorphic birds
have only singing males.
I have banded a few Varied Thrushes and forget how we aged them, other
than skull. With thrushes tail feather shape is quite reliable, the
youngsters having narrow and pointed tail feathers. It all depends on
the moult though, and you probably have looked at Pyle to figure all
that out.
Alvaro Jaramillo, Alviso, CA
I had previously sent my comments to Angus Wilson regarding my thoughts
on the Varied Thrush, but I am repeating them per his request to make
comments public. I had
several brief but decent looks at the Varied Thrush Sunday morning. My
thoughts are that it is an immature male, for the following reasons. The
dark mask contrasted strongly with
the bright and clearly defined orange supercilium, as well as with the
orange throat. The clear definition is stronger than any illustrations I
checked for female Varied Thrush. I did not
see any breast band, which would indicate a female, but the clear and
strong definition of the facial pattern makes me think it's a male. Also
the bird was singing. I had taped a copy
of the song from Peterson's Western bird calls. To my ears there were 2
types: one a long drawn out whistle, and the second similar, but with a
more "burry" texture, for lack of a
better word. The bird responded at times to the tape, but only with the
second "burry" call, which at times was quite loud. The combination of
the singing and the strong facial
pattern made me believe it was an immature male. Interestingly, I can
find no reference as to whether the Varied Thrush is a second or 3rd
year bird in the books I have. That
includes Sibley, Peterson, National Geo, Golden Guide, the Master Guide
series by Audubon, and the old North American Birds with the Fuertes
paintings. This last book gives
an extremely detailed description, but for adult birds only. Maybe one
of the old Bent Life Histories books might have more info.
Dave Klauber, NY
[ << | >> | ^^ ]
Subject: Re: Varied Thrush Puzzle
From: Julian Hough <Jrhough1(AT)AOL.COM>
Date: 18 Mar 2003 11:15am
Forgive me for sounding flippant,it is no reflection on anybody, but allow me a
lighthearted comment..
As someone once said with regards to a two bird theory,
"that's one too many!!!"
or...maybe its of the confusing subspecies Zoothera Transvestitus!!!
Best,
Julian Hough,
CT, USA
[ << | >> | ^^ ]
Subject: Re: Varied Thrush Puzzle
From: Tony Leukering <GreatGrayOwl(AT)AOL.COM>
Date: 18 Mar 2003 11:17am
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Hi all:
While I have virtually no experience with singing Varied Thrushes (well,
actually, none), I will say that there are so many passerine species in which
females sing (many more than I would have guessed just a few years ago) that
I would be very hesitant to identify the NY VATH as a male, solely on the
basis of song (and against the obvious plumage features telling us that the
bird is a female).
If you think about where most VATHs breed (I'm not talking about that
short-statured willow habitat in western Alaska that VATHs call breeding
habitat), how many times does one actually see a singing VATH? The species
is also relatively little studied, another red flag in making definitive
statements such as, "Female VATHs do not sing."
George (2000) states a number of times items along this line, "Other aspects
of the breeding biology of this species remain poorly known." Also in that
reference, he describes aspects of song in the species but nowhere states
that females do not sing. In fact, nowhere in the Sounds section is song
attributed to males, except that they "respond to taped song playback with
countersinging..." and that they "generally sing from top of live conifers;
rarely from snags, logs, or ground (Beck 1997)."
So, while it may be that males are the only VATHs that sing, I would say that
this thesis is far from proven.
Literature Cited
Beck, M. 1997. reference cited in George (2000).
George, T. L. 2000. Varied Thrush (Ixoreus naevius). In The Birds of North
America,
No. 541 (A. Poole and F. Gill, eds.). The Birds of North America,
Inc.,
Philadelphia, PA.
Enjoy,
Tony Leukering
Brighton, CO
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Subject: Re: Varied Thrush Puzzle
From: Les Chibana <les(AT)BIRDNUTZ.COM>
Date: 18 Mar 2003 2:00pm
I thought that it was hilarious that Alvaro and I sexed this bird
differently! In reality, we've seen only a small amount of Varied
Thrushes hitting the nets where we've banded. And now that he
mentioned it, I don't recall ever seeing a VATH without a breast
band either. And on 2nd thought, the facial pattern is a lot darker
than I would expect for a SY female that lacks a breast band.
I suppose that the bit of gray/grey lesser coverts/scapulars showing
between the branches could indicate a SY male or even ASY female.
I gave more weight to the lack of breast band, for which I don't have
any real basis for except Pyle's account.
In reconsidering, I'd have to say that I don't know what age or sex
this bird appears to be. I guess I haven't studied them enough. So
much for the high degree of confidence rating for ageing and sexing
indicated in Pyle.
Tony makes a good point. I have only once seen VATH making the
call note, and never seen them singing (in CA or AK). So, I can't
vouch either way, that males only sing or that females also sing.
I suppose that I can't even be so sure that the buzzy "vree" that I
hear is a VATH.
Les Chibana, Palo Alto CA
On Tuesday, March 18, 2003, at 08:54 AM, Angus Wilson wrote:
> In response to my earlier posting, two regular contributors to ID-F
> from
> California sent me their thoughts on the 'singing female' Varied Thrush
> from Long Island, New York. Both make good points and I hope they don't
> mind me sharing them with the whole group. Also Dave Klauber, a
> co-observer of the bird in question, offered his impressions of the
> vocalizations. I guess one possibility is that the bird is in fact a
> male (hormonally at least) that for some reason has not developed the
> appropriate plumage? Another theory, these plausible scenario would be
> a
> second (male) Varied Thrush, singing from a grassy knoll just out of
> sight. Perhaps Oliver Stone can comment on this :)
>
> Cheers, Angus Wilson
>
> *************************************
>
> Looks like a female to me. I have both sexes wintering in the forest
> around us this year (a good year for them, locally). The adult males
> are
> a nice slate gray in the dark plumage. This bird looks like a Second
> Year (SY) female from the indistinct breast band and brown dark
> markings. A SY male would have a more definite breast band. The graphic
> for this species account in Pyle shows that SY and After Second Year
> (ASY) birds can be aged and sexed with a high degree of confidence in
> March. I know nothing about the different races, which appear to be
> differentiated in the female plumage and breeding range. It appears
> that
> we could see all four in a central CA winter.
>
> I am only aware of the "vree" song notes and the "tschook" call note.
> The song often sounds half-hearted (less developed) through winter, and
> gets more drawn out and buzzier when sung just before they depart from
> the wintering areas and on the breeding grounds (like in Alaska). I
> wonder if the females are capable of singing a less- developed song as
> in the Carpodacus finches? I haven't found any references that say so,
> however.
>
> Les Chibana, Palo Alto CA
>
>
> A couple of very quick thoughts. I have never seen any Varied Thrush
> lacking a breast band, this is really an odd trait no matter what age
> or
> sex you consider the bird to be. However, missing band more likely on
> younger birds or female, I agree. Darkness of the face and the real
> blue-grey tone to the back looks good for male. Have no data on singing
> females in Varied Thrush, I have never seen a female American Robin
> singing, that is the best I can do. If it was me, I would put the
> singing behaviour as a clearer sign of sex than the plumage but that is
> from biases I have. Looking at blackbirds vocal behaviour is very sex
> dependent with certain vocalizations given by one sex and one sex only,
> while in others it is variable. Most migratory, sexually dimorphic
> birds
> have only singing males.
>
> I have banded a few Varied Thrushes and forget how we aged them, other
> than skull. With thrushes tail feather shape is quite reliable, the
> youngsters having narrow and pointed tail feathers. It all depends on
> the moult though, and you probably have looked at Pyle to figure all
> that out.
>
> Alvaro Jaramillo, Alviso, CA
>
>
> I had previously sent my comments to Angus Wilson regarding my thoughts
> on the Varied Thrush, but I am repeating them per his request to make
> comments public. I had
> several brief but decent looks at the Varied Thrush Sunday morning. My
> thoughts are that it is an immature male, for the following reasons.
> The
> dark mask contrasted strongly with
> the bright and clearly defined orange supercilium, as well as with the
> orange throat. The clear definition is stronger than any illustrations
> I
> checked for female Varied Thrush. I did not
> see any breast band, which would indicate a female, but the clear and
> strong definition of the facial pattern makes me think it's a male.
> Also
> the bird was singing. I had taped a copy
> of the song from Peterson's Western bird calls. To my ears there were 2
> types: one a long drawn out whistle, and the second similar, but with a
> more "burry" texture, for lack of a
> better word. The bird responded at times to the tape, but only with the
> second "burry" call, which at times was quite loud. The combination of
> the singing and the strong facial
> pattern made me believe it was an immature male. Interestingly, I can
> find no reference as to whether the Varied Thrush is a second or 3rd
> year bird in the books I have. That
> includes Sibley, Peterson, National Geo, Golden Guide, the Master Guide
> series by Audubon, and the old North American Birds with the Fuertes
> paintings. This last book gives
> an extremely detailed description, but for adult birds only. Maybe one
> of the old Bent Life Histories books might have more info.
>
> Dave Klauber, NY
>
[ << | >> | ^^ ]
Subject: Re: Varied Thrush Puzzle
From: Mike Patterson <celata(AT)pacifier.com>
Date: 18 Mar 2003 3:38pm
http://home.pacifier.com/~neawanna/temp/vath.html
and females will buzz in the winter...
--
Mike Patterson
Astoria, OR
celata(AT)pacifier.com
A child who becomes acquainted with the birds about him
hears every sound and puzzles out its meaning with a cleverness
that amazes those with ears who hear not.
-Neltje Blanchan
http://www.pacifier.com/~mpatters/bird/bird.html
[ << | >> | ^^ ]
Subject: Re: Varied Thrush Puzzle
From: Angus Wilson <wilsoa02(AT)MED.NYU.EDU>
Date: 18 Mar 2003 7:46pm
Thanks to everyone who has contributed so far. Keep 'em coming! I am
forwarding some comments from David Spector who is unable to post to the
list. One thing I forgot to mention before about the Long Island Varied
Thrush is that someone played a tape once or twice. I don't know whether
this might incite a burst of song?
Cheers, Angus Wilson
********************************
There are records of female song for many species of temperate zone,
migrant species in which normally the males do all of the singing. For
example, there are records of rare female song from at least ten North
American wood-warblers (I can give you references if you want). Also,
females (even in species in which females do not normally sing) can often
be induced to sing with testosterone implants; there is no inherent
absolute barrier to singing by females in these species. There is the
possibility that a bird that is aberrant in one behavior (flying to the
East) is more likely to be aberrant in another behavior (singing as a
female in a species that normally does not have female song).
Thanks for sharing this intriguing bird,
David
David Spector, New Britain, Connecticut
[ << | >> | ^^ ]
Subject: VA Beach Gull
From: John Puschock <g_g_allin(AT)HOTMAIL.COM>
Date: 18 Mar 2003 9:28pm
Martin Reid has posted several of my photos of a gull seen on the March 1
pelagic trip out of Virginia Beach, Virginia. The photos are posted at
http://www.martinreid.com/gullsp33.html.
The interesting thing about this gull was the relatively light gray of the
upperparts and the limited amount of black in the primaries. In direct
comparison, it was obviously darker than Herring Gulls -- it wasn't
difficult to pick it out of the gull flock following the boat -- but lighter
than other Lesser Black-backeds I've seen (all in the eastern U.S.).
Assuming the Kodak gray scale printed in the latest issue of Birding is
accurate, I'd describe it as a 7 or perhaps slightly lighter.
I'd like to hear opinions on the possible identity of this gull. Does it
appear to be within the range of Lesser Black-backed Gull or is it better
described as a probable Herring x Lesser Black-backed hybrid (or anything
else)?
For the most part, I'll let the photos speak for themselves -- I spent most
of my time trying to get the photos rather than observing the bird. I did
lighten the scans a bit to try to match the shade of gray in the original
slides, but I didn't make any color corrections. (The film was Fuji Provia
400 and the scans were made on a 13-inch laptop monitor.) On my monitor,
the first flight shot looks a little darker than the original slide. In the
bottom left photo, the orbital ring appears to be orange-red; however, it
appears red in the originals. Leg color was unquestionably yellow -- it
didn't strike me as being any different than the leg color of a typical
Lesser Black-backed. Also, that's a Herring Gull on the left in the top
photo.
John Puschock
g_g_allin(AT)hotmail.com
_________________________________________________________________
The new MSN 8: advanced junk mail protection and 2 months FREE*
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[ << | >> | ^^ ]
Subject: Identification of Brant - Variability and
hybridization
From: Angus Wilson <wilsoa02(AT)MED.NYU.EDU>
Date: 18 Mar 2003 11:37pm
Re: An 'intermediate brant' from New York: photos and discussion
Hi everyone, I have put together some pictures of an interesting brant goose
taken on Long Island, New York in January of this year.
http://www.oceanwanderers.com/IntrmBrantNY.html
The bird is one of the puzzling 'intermediate-types' that we've been seeing on
a regular basis during the past few years. It was present in a small flock of
Low-Arctic Atlantic Brant (aka Pale-bellied Brent Geese) that also included a
conventional Black Brant. The latter is now an annual vagrant to the area.
At this point, we really don't know what these 'intermediate' birds are exactly
but in hopes of stimulating discussion, I review the three leading
possibilities. At the bottom of the page there are several links to older web
pages showing similar birds from previous winters. Some will be familiar to ID-
F regulars but may still be worth revisiting with a fresh eye.
As always I look forward to your comments on these interesting and mysterious
birds and would urge everyone to share their thoughts or photographs with the
entire list. It is clear that there are still many gaps in our knowledge of
North American brant.
Cheers, Angus Wilson
New York City
http://www.oceanwanderers.com
-------------------------------------------------
This mail sent through IMP: http://horde.org/imp/
[ << | >> | ^^ ]
Subject: Re: Varied Thrush Puzzle
From: Nathan Hentze <w_tanager(AT)HOTMAIL.COM>
Date: 19 Mar 2003 12:31am
Hello all,
As for the sex of the NY bird I think that it is a male, possibly SY, for
reasons stated by others so I won't repeat them again. I am glad that this
discussion has arisen, as I have been pondering an individual I observed
last year. On Feb. 13, 2002 at my home on eastern Vancouver Island, BC I
observed at relatively close range (<15ft) a VATH that in all aspects I
could see appeared to be a male (dark slate-blue crown and back, etc) with
other VATH of both sexes nearby for comparison. The unusual thing was that
save for about 1cm of dark where the breastband should begin, the entire
breast was orange. A nearly identical pattern to the bird in question. I
have been paying closer attention to my local VATH breastbands since then,
and have never seen another individual of any sex that completely lacked
it. Females seem to show more variation in completeness of the breastband,
with some birds observed having the very centre of the breast with a split
of orange feathering, or orange feathering intermixed with the gray-brown
band. In another unusual variant I observed this previous weekend, a male
had a breastband that was about 2x wider than normal, leaving only the chin
and very upper throat orange. So in summary, from my personal observations
females show more individual variation in breastband completeness, but
males have shown the most extreme variations. I think it is quite
plausible that any age or sex of VATH may lack or partially lack a
breastband.
Thanks for bringing this topic to light,
Nathan Hentze,
Cumberland, BC, Canada
On Tue, 18 Mar 2003 00:32:31 -0500, Angus Wilson <wilsoa02(AT)MED.NYU.EDU>
wrote:
>Do west coast birders or museum collection managers know of proven males
that
>show a very weak breast band? Is there evidence for singing by female
Varied
>Thrushes, or other _Zoothera_ thrushes for that matter?
>
>Cheers, Angus Wilson
>New York City
>http://www.oceanwanderers.com
[ << | >> | ^^ ]
Subject: Re: VA Beach Gull
From: Nick Rossiter <nrossiter(AT)SUPANET.COM>
Date: 19 Mar 2003 7:51am
Interesting gull with good wingtip shots.
It's not likely to be graellsii as there is too little black in the wingtip
(P7 has long grey tongues) and too much white (almost complete tip P10, large
mirror P9).
It's not Azorean or Southern atlantis as there is too little black in the
wingtip (P7 has long grey tongues). The amount of white on P9 is also very
untypical for these forms.
It might be an Iberian atlantis as these can have more strongly indented black
on the wingtip and more white on P9. They are slightly darker than michahellis
-- around 7 on Kodak grey scale.
It's most like cantabricans (Cantabrican Atlantic YLG) from northern Spain/SW
France which can be thought of as a Herring Gull (argenteus) in biometrics,
calls and wingtip pattern but with slightly darker mantle and finer bill. This
form tends slightly paler than michahellis -- hence probably around 5-6 on the
Kodak grey scale. Also they can retain head markings well into spring. Ringing
shows they are not very mobile.
It could of course also be a yellow-legged smithsonianus but the mantle shade
seems too dark for this.
Another view would be that it's a hybrid graellsii x smithsonianus. Features
seem more extreme than intermediate e.g. wing-tip is classical Herring Gull.
The leg colour may be critical here. A hybrid would be expected to show some
fleshy tones in the legs themselves. As the legs are bright yellow I would
discount a hybrid.
So I think this is an Atlantic YLG from northern Iberia – typical cantabricans
or less typical Iberian atlantis.
Cheers … Nick
g_g_allin(AT)HOTMAIL.COM wrote:
> Martin Reid has posted several of my photos of a gull seen on the March 1
> pelagic trip out of Virginia Beach, Virginia. The photos are posted at
> http://www.martinreid.com/gullsp33.html.
>
> The interesting thing about this gull was the relatively light gray of the
> upperparts and the limited amount of black in the primaries. In direct
> comparison, it was obviously darker than Herring Gulls -- it wasn't
> difficult to pick it out of the gull flock following the boat -- but lighter
> than other Lesser Black-backeds I've seen (all in the eastern U.S.).
> Assuming the Kodak gray scale printed in the latest issue of Birding is
> accurate, I'd describe it as a 7 or perhaps slightly lighter.
>
> I'd like to hear opinions on the possible identity of this gull. Does it
> appear to be within the range of Lesser Black-backed Gull or is it better
> described as a probable Herring x Lesser Black-backed hybrid (or anything
> else)?
>
> For the most part, I'll let the photos speak for themselves -- I spent most
> of my time trying to get the photos rather than observing the bird. I did
> lighten the scans a bit to try to match the shade of gray in the original
> slides, but I didn't make any color corrections. (The film was Fuji Provia
> 400 and the scans were made on a 13-inch laptop monitor.) On my monitor,
> the first flight shot looks a little darker than the original slide. In the
> bottom left photo, the orbital ring appears to be orange-red; however, it
> appears red in the originals. Leg color was unquestionably yellow -- it
> didn't strike me as being any different than the leg color of a typical
> Lesser Black-backed. Also, that's a Herring Gull on the left in the top
> photo.
>
> John Puschock
> g_g_allin(AT)hotmail.com
>
>
>
>
>
> _________________________________________________________________
> The new MSN 8: advanced junk mail protection and 2 months FREE*
> http://join.msn.com/?page=features/junkmail
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Message sent with Supanet E-mail
[ << | >> | ^^ ]
Subject: Plumage variation in Varied Thrush
From: Julian Hough <Jrhough1(AT)AOL.COM>
Date: 19 Mar 2003 10:27am
I looked again at Angus Wilson's photos and although I can't see the
darkness/grayness of the upperparts, I think that the auriculars, if as dark in
life, suggest a male, albeit an atypical one which is totally lacking a
breastband!
Given the input from observers of the NY bird, and if we assume that males are
the only(?) ones to sing, this seems the most logical explanation.
I think that Varied Thrush plumages are probably more variable than we think
(hence its name??).
When you consider that the only Western Palearctic record (Cornwall, England in
November 1982) completely lacked any orange pigment in the plumage, a bird
lacking a breastband doesn't seem too surprising.
Cheers,
Julian Hough,
CT, USA
[ << | >> | ^^ ]
Subject: Re: Plumage variation in Varied Thrush
From: Matt Kenne <mkenne(AT)NETAMUMAIL.COM>
Date: 19 Mar 2003 11:35am
This is a multi-part message in MIME format.
----INCLUDING text/plain MIME SECTION----
You can see a Varied Thrush without a breastband AND without orange =
coloration on Don Roberson's thrush family page =
http://montereybay.com/creagrus/thrushes.html
Matthew Kenne
Algona, Iowa
mkenne(AT)netamumail.com
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[ << | >> | ^^ ]
Subject: Re: Winter Laughing Gulls
From: Ian Mclaren <iamclar(AT)DAL.CA>
Date: 19 Mar 2003 12:45pm
All, especially east coasters:
I am dealing with a CBC observation at the head of the Bay of Fundy of
what were well described by reliable observers (but beginnerish birders)
as four Laughing Gulls. These are not unprecedented here in early winter
and indeed on a few past CBCs.
The description of size, mantle/upperwing tone, and wing tips seem right,
althought the birds weren't close enough to show eye-crescents. However,
two of the birds had black (blackish?) heads. This isn't supposed to be
per literature available. But, does it ever in reality occur?
Answer me directly if you think this is not a suitable/interesting topic.
Cheers, Ian
Ian A. McLaren, PhD
Professor Emeritus Phone (W) 902-494-2565
Biology Department Fax 902-494-3736
Dalhousie University Phone (H) 902-429-7024
Halifax, NS B3H 4J1
[ << | >> | ^^ ]
Subject: Re: Varied Thrush Puzzle
From: Tony Leukering <GreatGrayOwl(AT)AOL.COM>
Date: 19 Mar 2003 4:15pm
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Hi all:
I have one more piece of info to provide:
In spring 1987 when I was working at American Birds in NYC, I chased a VATH
that a friend found at Battery Park (southern tip of Manhattan). The bird
was obviously a VATH, but had only a ghost of a breast band. At the time, I
assumed that the bird was a female, but it did look dark-crowned and
dark-backed - needless to say, I was confused, especially since it was my
life VATH. So, though VATHs without (or with greatly reduced) breast bands
seem rare, they are not exceedingly so.
Perhaps this thread will encourage more careful study of VATHs!
Tony Leukering
Brighton, CO
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[ << | >> | ^^ ]
Subject: Re: Winter Laughing Gulls
From: Tony Leukering <GreatGrayOwl(AT)AOL.COM>
Date: 19 Mar 2003 4:22pm
----INCLUDING text/plain MIME SECTION----
Hi Ian and others:
A couple years ago, an adult Franklin's Gull spent the winter here in the
Barr Lake, CO, vicinity in complete Alternate plumage - even down to the pink
wash on the body. Additionally, I have heard of, but not seen, individual
hooded gulls, specifically Bonaparte's, on CBCs. However, I have never seen,
nor heard of, a winter Alternate-plumaged Laughing, but I would not at all
say that it couldn't happen.
However, four together seems exceedingly unlikely.
Tony Leukering
Brighton, CO
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[ << | >> | ^^ ]
Subject: Re: Winter Laughing Gulls
From: Matt Kenne <mkenne(AT)NETAMUMAIL.COM>
Date: 19 Mar 2003 7:28pm
This is a multi-part message in MIME format.
----INCLUDING text/plain MIME SECTION----
We've also had a few mid-winter alternate plumage Franklin's Gulls on =
Iowa reservoirs, although they were single birds sighted in different =
years. I can't say I understand the phenomenon, but it's not a great =
leap to project it onto Laughing Gulls.
Matthew Kenne
Algona, Iowa
mkenne(AT)netamumail.com
----- Original Message -----=20
From: Tony Leukering=20
To: BIRDWG01(AT)listserv.arizona.edu=20
Sent: Wednesday, March 19, 2003 5:22 PM
Subject: Re: [BIRDWG01] Winter Laughing Gulls
Hi Ian and others:
A couple years ago, an adult Franklin's Gull spent the winter here in =
the Barr Lake, CO, vicinity in complete Alternate plumage - even down to =
the pink wash on the body. Additionally, I have heard of, but not seen, =
individual hooded gulls, specifically Bonaparte's, on CBCs. However, I =
have never seen, nor heard of, a winter Alternate-plumaged Laughing, but =
I would not at all say that it couldn't happen.
However, four together seems exceedingly unlikely.
Tony Leukering
Brighton, CO=20
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[ << | >> | ^^ ]
Subject: Re: VA Beach Gull
From: Martin Reid <upupa(AT)AIRMAIL.NET>
Date: 20 Mar 2003 5:05am
Dear all,
I read with interest Nick Rossiter's comments on the VA gulls. I find a
couple of features on this bird puzzling for any form of YLGU:
The orbital ring appears yellowish - at best yellowish-orange. Care must
be taken when assessing bare parts colors, and John comments that in the
original image the orbital ring appears to be red - but the colors of the
bill provide a good reference for direct comparison in these two images,
and it is hard for me to accept that the gonydal spot appears the normal
red color while the orbital ring has somehow been color-shifted - ? LBBG
and all forms of YLGU (I think) have red or reddish orbital rings.
The pattern of black at the BASE of the primaries; On the upperside there
is a small amount of gray visible beyond the primary coverts on both P8 and
P9, rather than the black reaching the gray coverts. A close look at a
lightened version of the underside of the wing shows P9 and P8 to be almost
all-gray from below.
The upperside distal pattern of P8; the black on the inner web is very
short, and separated from the basal gray by an obvious white "pearl"
I know little about Cantabrican Gull, but here are some flight shots:
http://www.martinreid.com/mcanp06.html
If we remove YLGU from consideration for the sake of argument, what are we
left with? I feel that the primary pattern is not typical of the smith
HERGs I see in Texas (to little black, and "pearls" too conspicuous") - but
in Newfoundland there are smiths that have far less black in the primaries,
thus this individual could be a hybrid between such a HERG and a LBBG, I
suppose. The strongly yellow legs are odd for an F1 hybrid, and I might
expect an F2 (with smith) to look more HERG-like.
In some ways, this VA bird reminds me of the dark-backed gull from Texas:
http://www.martinreid.com/gullspx4.html - but this TX bird has more flesh
tones to the legs, a dark eye, red orbital, etc.
My personal feeling on the Texas bird is that it is likely a
taimyrensis/birulai hybrid. This form is highly variable in appearance;
check out the Ujihara's pages on taim. - most of which are hybrids, I think:
http://larus.hp.infoseek.co.jp/a_heuglini.html
- these birds have some distinct structure features that seem unlikely in
a eastern smith HERG x graellsii/intergrade LBBG.
Given that VA is a regular (?) haunt of Black-tailed gull(s), I feel we
should consider this possibility!
On a related ID gull topic - winter records of small gulls in Alternate
plumage - I'd like to add that I see about one or two adult FRGUs a year
in mid-winter (late Dec - late Jan) - and they ALL have been in breeding
plumage. I've also seen a BOGU on New Year's Day with a complete black
hood. If the biological clock is skewed enough for a gull to be at the
wrong temporal latitude (not applicable to BOGU, but to LAGU and FRGU) then
this may be in response to a mis-timed hormonal trigger, which could also
affect their appearance. I think this phenomenon is well-documented in
small gulls due to the obvious plumage change - the development of a
"black" head - but I wonder if this should also be considered a significant
factor in assessing large migratory gulls that appear at the wrong temporal
latitude? Just a thought.
Good gulling,
Martin
At 3/19/2003 04:27 AM +0000, you wrote:
>Martin Reid has posted several of my photos of a gull seen on the March 1
>pelagic trip out of Virginia Beach, Virginia. The photos are posted at
>http://www.martinreid.com/gullsp33.html.
>
>The interesting thing about this gull was the relatively light gray of the
>upperparts and the limited amount of black in the primaries. In direct
>comparison, it was obviously darker than Herring Gulls -- it wasn't
>difficult to pick it out of the gull flock following the boat -- but lighter
>than other Lesser Black-backeds I've seen (all in the eastern U.S.).
>Assuming the Kodak gray scale printed in the latest issue of Birding is
>accurate, I'd describe it as a 7 or perhaps slightly lighter.
>
>I'd like to hear opinions on the possible identity of this gull. Does it
>appear to be within the range of Lesser Black-backed Gull or is it better
>described as a probable Herring x Lesser Black-backed hybrid (or anything
>else)?
>
>For the most part, I'll let the photos speak for themselves -- I spent most
>of my time trying to get the photos rather than observing the bird. I did
>lighten the scans a bit to try to match the shade of gray in the original
>slides, but I didn't make any color corrections. (The film was Fuji Provia
>400 and the scans were made on a 13-inch laptop monitor.) On my monitor,
>the first flight shot looks a little darker than the original slide. In the
>bottom left photo, the orbital ring appears to be orange-red; however, it
>appears red in the originals. Leg color was unquestionably yellow -- it
>didn't strike me as being any different than the leg color of a typical
>Lesser Black-backed. Also, that's a Herring Gull on the left in the top
>photo.
>
>John Puschock
>g_g_allin(AT)hotmail.com
>
>
>
>
>
>_________________________________________________________________
>The new MSN 8: advanced junk mail protection and 2 months FREE*
>http://join.msn.com/?page=features/junkmail
Martin Reid
Fort Worth, Texas
mailto:upupa(AT)airmail.net
http://www.martinreid.com
[ << | >> | ^^ ]
Subject: RE : VA Beach Gull
From: =?iso-8859-1?Q?Pierre-Andr=E9_CROCHET?= <crochet(AT)CEFE.CNRS-MOP.FR>
Date: 20 Mar 2003 6:52am
Dear all,
I totally agree with Martin that this bird is very puzzling for any form of YLG.
The comment's by Nick Rossiter that Cantabrican YLG have wing tip pattern more
similar to Herring Gull is not supported by our analyses (Pons et al. in prep)
of specimens or our field experience. Cantabrican YLG are typical YLG when in
terms of wing tip pattern. There is a slight amount of variation when compared
to Mediterranean birds, but it is only in term of frequency of different
characters and there is a full overlap.
I think the wing tip pattern of this bird is outside the variation of any form
of YLG. I might be proved wrong of course, but this is my feeling when studying
the pictures.
Last, the theory that a large proportion of birds wintering in Japan are hybrids
or intergrades between vegae (inc. birulai) and taimyrensis is poorly
supported. There seems to be more variation in vegae that most people recognise.
The birds breeding in the N. Taimyr peninsula seem to correspond to what some
people call taimyrensis~vegae intergrades (pictures can be seen in Filchagov et
al. 1992, l'Oiseau et RFO 62:128-148). But the fact that the population breeding
there is very homogenous and far from the presumed intergradation zone (SW
Taimyr) speaks against this theory. Now, it might be that there has been in the
past some intergradation between heuglini/taimyrensis and vegae/birulae and that
the characters of the western vegae populations partly derive from this
phenomenon. Similarly, the there are strong arguments to suggest that the yellow
legged genes of the eastern argentatus populations originate from introgression
(from what?). Or that barabensis might have gaine!
d some of its morphological characters through past introgression with
cachinnans. Still, it does not make them intergrades. The difference is whether
there is ongoing gene flow and hybridisation, or whether an ancient event of
introgression is involved. Present evidence support the last theory.
Finally, I have no idea what the VA Beach Gull can be...
Best,
Pierre-Andre
Pierre-André Crochet
CEFE-CNRS
1919, route de Mende
34293 Montpellier cedex 5
France
tel: + 33 6 07 32 60 75
fax: + 33 4 67 41 21 38
crochet(AT)cefe.cnrs-mop.fr
-----Message d'origine-----
De : Martin Reid [mailto:upupa(AT)AIRMAIL.NET]
Envoyé : jeudi 20 mars 2003 13:08
À : BIRDWG01(AT)listserv.arizona.edu
Objet : Re: [BIRDWG01] VA Beach Gull
Dear all,
I read with interest Nick Rossiter's comments on the VA gulls. I find a
couple of features on this bird puzzling for any form of YLGU:
The orbital ring appears yellowish - at best yellowish-orange. Care must
be taken when assessing bare parts colors, and John comments that in the
original image the orbital ring appears to be red - but the colors of the
bill provide a good reference for direct comparison in these two images,
and it is hard for me to accept that the gonydal spot appears the normal
red color while the orbital ring has somehow been color-shifted - ? LBBG
and all forms of YLGU (I think) have red or reddish orbital rings.
The pattern of black at the BASE of the primaries; On the upperside there
is a small amount of gray visible beyond the primary coverts on both P8 and
P9, rather than the black reaching the gray coverts. A close look at a
lightened version of the underside of the wing shows P9 and P8 to be almost
all-gray from below.
The upperside distal pattern of P8; the black on the inner web is very
short, and separated from the basal gray by an obvious white "pearl"
I know little about Cantabrican Gull, but here are some flight shots:
http://www.martinreid.com/mcanp06.html
If we remove YLGU from consideration for the sake of argument, what are we
left with? I feel that the primary pattern is not typical of the smith
HERGs I see in Texas (to little black, and "pearls" too conspicuous") - but
in Newfoundland there are smiths that have far less black in the primaries,
thus this individual could be a hybrid between such a HERG and a LBBG, I
suppose. The strongly yellow legs are odd for an F1 hybrid, and I might
expect an F2 (with smith) to look more HERG-like.
In some ways, this VA bird reminds me of the dark-backed gull from Texas:
http://www.martinreid.com/gullspx4.html - but this TX bird has more flesh
tones to the legs, a dark eye, red orbital, etc.
My personal feeling on the Texas bird is that it is likely a
taimyrensis/birulai hybrid. This form is highly variable in appearance;
check out the Ujihara's pages on taim. - most of which are hybrids, I think:
http://larus.hp.infoseek.co.jp/a_heuglini.html
- these birds have some distinct structure features that seem unlikely in
a eastern smith HERG x graellsii/intergrade LBBG.
Given that VA is a regular (?) haunt of Black-tailed gull(s), I feel we
should consider this possibility!
On a related ID gull topic - winter records of small gulls in Alternate
plumage - I'd like to add that I see about one or two adult FRGUs a year
in mid-winter (late Dec - late Jan) - and they ALL have been in breeding
plumage. I've also seen a BOGU on New Year's Day with a complete black
hood. If the biological clock is skewed enough for a gull to be at the
wrong temporal latitude (not applicable to BOGU, but to LAGU and FRGU) then
this may be in response to a mis-timed hormonal trigger, which could also
affect their appearance. I think this phenomenon is well-documented in
small gulls due to the obvious plumage change - the development of a
"black" head - but I wonder if this should also be considered a significant
factor in assessing large migratory gulls that appear at the wrong temporal
latitude? Just a thought.
Good gulling,
Martin
At 3/19/2003 04:27 AM +0000, you wrote:
>Martin Reid has posted several of my photos of a gull seen on the March 1
>pelagic trip out of Virginia Beach, Virginia. The photos are posted at
>http://www.martinreid.com/gullsp33.html.
>
>The interesting thing about this gull was the relatively light gray of the
>upperparts and the limited amount of black in the primaries. In direct
>comparison, it was obviously darker than Herring Gulls -- it wasn't
>difficult to pick it out of the gull flock following the boat -- but lighter
>than other Lesser Black-backeds I've seen (all in the eastern U.S.).
>Assuming the Kodak gray scale printed in the latest issue of Birding is
>accurate, I'd describe it as a 7 or perhaps slightly lighter.
>
>I'd like to hear opinions on the possible identity of this gull. Does it
>appear to be within the range of Lesser Black-backed Gull or is it better
>described as a probable Herring x Lesser Black-backed hybrid (or anything
>else)?
>
>For the most part, I'll let the photos speak for themselves -- I spent most
>of my time trying to get the photos rather than observing the bird. I did
>lighten the scans a bit to try to match the shade of gray in the original
>slides, but I didn't make any color corrections. (The film was Fuji Provia
>400 and the scans were made on a 13-inch laptop monitor.) On my monitor,
>the first flight shot looks a little darker than the original slide. In the
>bottom left photo, the orbital ring appears to be orange-red; however, it
>appears red in the originals. Leg color was unquestionably yellow -- it
>didn't strike me as being any different than the leg color of a typical
>Lesser Black-backed. Also, that's a Herring Gull on the left in the top
>photo.
>
>John Puschock
>g_g_allin(AT)hotmail.com
>
>
>
>
>
>_________________________________________________________________
>The new MSN 8: advanced junk mail protection and 2 months FREE*
>http://join.msn.com/?page=features/junkmail
Martin Reid
Fort Worth, Texas
mailto:upupa(AT)airmail.net
http://www.martinreid.com
[ << | >> | ^^ ]
Subject: Re: Winter Laughing Gulls
From: "D. Heindel" <birdfish(AT)EARTHLINK.NET>
Date: 20 Mar 2003 8:24am
----DELETED HTML-ENCODED SECTION----
[ << | >> | ^^ ]
Subject: Re: Winter Laughing Gull
From: Ian Mclaren <iamclar(AT)DAL.CA>
Date: 20 Mar 2003 8:41am
Thanks to all who replied personally or on the list. I've decided to list
the birds as "Gull sp.," and will perhaps include a comment in my short
account of this year's Atlantic Canada CBCs.
THere seems to be a consensus that alternate plumage in winter would be
very rare or absent in Laughing Gull, but occasional in Franklin's.
Although the latter has also been seen here very rarely in early winter,
I don't think it can be safely offered as an alternative.
Cheers, Ian M.
Ian A. McLaren
Biology Department Fax 902-494-3736
Dalhousie University Phone (H) 902-429-7024
Halifax, NS B3H 4J1
[ << | >> | ^^ ]
Subject: Re: Winter Laughing Gull
From: Alvaro Jaramillo <chucao(AT)ATTBI.COM>
Date: 20 Mar 2003 9:42am
At 11:41 AM 3/20/2003 -0400, Ian Mclaren wrote:
>Thanks to all who replied personally or on the list. I've decided to list
>the birds as "Gull sp.," and will perhaps include a comment in my short
>account of this year's Atlantic Canada CBCs.
>
>THere seems to be a consensus that alternate plumage in winter would be
>very rare or absent in Laughing Gull, but occasional in Franklin's.
>Although the latter has also been seen here very rarely in early winter,
>I don't think it can be safely offered as an alternative.
There are some general patterns in gulls/shorebirds in the wrong plumage
for the season. At least I think there are. The key to understanding this
is to think of where they winter. Birds that winter in the northern
hemisphere are "programmed" to think that spring is coming when day length
begins to increase. Birds that winter in the southern hemisphere are
"programmed" to think that their spring is coming when day length begins to
decrease (because they are thinking spring, when its actually fall in the
southern hemisphere!). So northern hemisphere/tropical wintering birds that
overshoot and wind up in winter (boreal winter) much farther south may gain
a breeding plumage (in boreal winter) if that individual reacts strongly to
the day light changes it encounters there. This may explain why a couple of
the Short-billed Dowitcher records from Argentina (in boreal winter) were
of breeding plumaged birds, and why at least two records of Laughing Gull
(in boreal winter) in Chile were of birds in breeding plumage. This doesn't
mean that every time a northern hemisphere winterer overshoots it will
obtain a messed up plumage, but its more likely to happen in this situation
than in any other. Similarly birds that typically winter in the southern
hemisphere but for some reason remain in the northern hemisphere may obtain
a breeding plumage at the wrong time of the year. If a Franklin's Gull
winters in North America, once its internal physiology switches from
migration mode to wintering mode it could potentially react to shortening
day lengths (in late fall and early winter) and obtain a breeding plumage
during the boreal winter. Again, it won't happen every time but its more
likely to happen than in other situations.
A lot of species (examples - Sanderling, Red Knot, Ruddy Turnstone
etc.) winter through a wide latitudinal range, a huge latitudinal range
actually. In these cases the pattern I noted above will not apply. But, I
bet that if you took a group of Red Knots that winter here in the San
Francisco Bay and you released them in Bahia Lomas in southern Patagonia in
the fall, some of those birds would switch plumage. Its dependent on what
the individual populations are "programmed" to do.
I think its a plausible explanation, but entirely untested. Perhaps others
can come up with patterns in the birds they know which could show that this
seldom applies, or perhaps that it does account for odd plumages they have
encountered.
So what about the gulls in the Maritimes? Based on this hypothesis, they
would be more likely to be Franklin's Gulls than Laughing Gulls - but
surely it isn't this simple.
cheers,
Al
Alvaro Jaramillo
Biologist
San Francisco Bay Bird Observatory
P.O. Box 247
Alviso, CA 95002
(408)-946-6548
http://www.sfbbo.org/
chucao(AT)attbi.com
[ << | >> | ^^ ]
Subject: Winter LAGU
From: Gavin Bieber <kingbird77(AT)HOTMAIL.COM>
Date: 20 Mar 2003 10:01am
Hello All,
A quick note on the Laughing Gull thread. I have seen a few fully hooded
Laughing Gulls along the upper Gulf coast (mississippi and alabama) as early
as mid Jan.
Gavin Bieber
Kingbird77(AT)hotmail.com
Tucson, AZ
_________________________________________________________________
STOP MORE SPAM with the new MSN 8 and get 2 months FREE*
http://join.msn.com/?page=features/junkmail
[ << | >> | ^^ ]
Subject: Re: VA Beach Gull
From: Peter Adriaens <peter.adriaens(AT)DUTCHBIRDING.NL>
Date: 20 Mar 2003 10:50am
Hi,
I tried to post on this bird before, but my message apparently did not get
through.
Now Martin and Pierre-André have said the most... Perhaps I may contribute in
some
way by confirming that the primary pattern is indeed quite similar to that of
some
Newfoundland Herring Gulls (which also means that it is certainly not typical of
any
Yellow-legged Gull). The extent of its head streaking (with some spots/blotches
in
the neck) is also unlike Yellow-legged Gull, as is the rather dull bill pattern
(the
gonys spot is not bright red, and it does not reach on to the upper mandible;
there is
also a slight blackish band at the gonys).
In addition, I would like to point out that several adult hybrid gulls that have
bred in
Belgium in recent years, have shown quite yellow legs. This includes one
colour-
ringed bird (ringed by Norman Van Swelm in The Netherlands as a Herring x
Yellow-legged Gull). There are no guarantees that leg colour in a hybrid will
always
be intermediate between that of its parents. Even 'pure' Herring Gulls may show
yellow legs.
I feel this has to be a hybrid smithsonianus x graellsii.
Best regards,
Peter Adriaens
Belgium
[ << | >> | ^^ ]
Subject: VA Beach Gull
From: Nick Rossiter <nrossiter(AT)SUPANET.COM>
Date: 20 Mar 2003 1:24pm
This is a multi-part message in MIME format.
----INCLUDING text/plain MIME SECTION----
I'm not sure that everyone has looked at the cantabricans on Martin =
Reid's web site at:
http://www.martinreid.com/mcanp06.html
This page shows a range of typical cantabricans adults. The wingtips of =
these birds are not typical michahellis. True P9 and P10 are similar to =
those of Mediterranean michahellis (plenty of white) and hence to =
argenteus. But the middle primaries are different. In general these =
show less tendency to black on P4, more likelihood of a spot or a thin, =
broken band on P5 and a greater tendency to a marked pale grey indent =
into the solid black area of the wingtip.=20
My own studies show a similar picture. See=20
http://www.nrossiter.supanet.com/ylg/cantylg.htm
for details.=20
In addition the literature abounds with information on the =
argenteus-like features of cantabricans including an orange-red orbital =
ring and extensive head markings into spring. I will give more details =
if required but see Martin Garner & David Quinn, p.58-59 90(1-2), in =
their British Birds article from January-February 1997 for a start.=20
I think to some extent we're into classification problems. I only regard =
cantabricans as an Atlantic Yellow-legged Gull in the broadest sense. It =
does not fit well with the atlantis from further south and I would not =
classify it as such. The clasification of cantabricans is very =
debatable. It could even be included under argenteus (after all some =
argentatus have yellow legs). I think Pierre's DNA studies have linked =
it with michahellis.=20
Obviously M. Pons information on cantabricans would be very welcome but =
we can only go on the evidence in the public domain. Is there any chance =
of making some summary information available perhaps? That would be a =
great help.=20
Best wishes ... Nick
=20
Citing unpublsihed results does not realy advance the debate unless =
you're going to release some information for us to see and evaluate. Is =
Mr Pons prepared to do this?
I'll call as evidence Martins Reid's site already mentioned in his =
message at:...=20
This pattern is much more like a Herring Gull than michahellis. In =
Mediterranean michahellis you often get a spot on P4, always a broad =
solid band on P5 and a solid black triangle to the wing tip.=20
See Paul Isenmann's seminal paper at
http://www.nrossiter.supanet.com/ylg/isenmann.htm
and Garner & Quinn (1997).=20
=20
Also see Teyseedre's paper on cantabricans=20
In reply to Martin's comments, cantabricans can show an orange-red =
orbital ring. Geographically cantabricans is sandwiched betweem Herring =
Gull (argenteus) in western France and Iberian atlantis in north-west =
Spain.=20
----DELETED text/html MIME SECTION----
[ << | >> | ^^ ]
Subject: Re: Winter Laughing Gull
From: Floyd Hayes <floyd_hayes(AT)YAHOO.COM>
Date: 20 Mar 2003 2:10pm
An estimated 5,000 Laughing Gulls winter along the
west coast of Trinidad. I recall seeing a few winter
birds retaining alternate plumage during one winter
and just did an electronic search through previous
Southeastern Caribbean Bird Alerts. Here's what I
found:
On 16 December 2000, one of 1500 had a solid black
hood (and really surprised me).
On 21 January 2001, four of 1567 had a solid black
hood (after which many began acquiring alternate
plumage).
I probably have additional observations in my field
notes but don't want to take the time to review them.
In any case, the above data illustrate that retention
of alternate plumage throughout the winter is quite
rare. I don't recall seeing any such birds during the
several other winters when I resided in Trinidad.
=====
Floyd E. Hayes
Wildlife Biologist
Division of Fish and Wildlife, 6291 Estate Nazareth,
St. Thomas, Virgin Islands 00802, USA
Tel: 340-775-6762; Fax: 340-775-3972
Website: http://www.geocities.com/floyd_hayes
__________________________________________________
Do you Yahoo!?
Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop!
http://platinum.yahoo.com
[ << | >> | ^^ ]
Subject: Fwd: Re: Winter Laughing Gull
From: Alvaro Jaramillo <chucao(AT)ATTBI.COM>
Date: 21 Mar 2003 12:07am
Folks,
Don Roberson sent me this note, and gave me permission to forward it to
the group.
>Date: Thu, 20 Mar 2003 09:46:29 -0800
>From: creagrus <creagrus(AT)montereybay.com>
>
>Al -- an excellent discussion on this topic! You wrote: "I think its a
>plausible explanation, but entirely untested...." Perhaps it HAS been
>'tested' somewhat beyond the annectodol records you mention. The
>Monterey Bay Aquarium takes in for their aviary injured shorebirds found
>in coastal California. They are held in an aviary that has extensive
>light coming through the roof and windows as it faces the ocean, and
>presents an 'unnatural' lighting situation. A surprising percentage of
>shorebirds there go into full alternate in mid-winter (particularly
>Thanksgiving to Xmas): Black-bellied Plover, Dunlin, both species of
>dowitchers, Red-necked Phalarope, etc. I've always believed it was the
>unnatural lighting and distorted day-length that caused these very odd
>molts.
>
>Cheers, Don
Alvaro Jaramillo
Biologist
San Francisco Bay Bird Observatory
P.O. Box 247
Alviso, CA 95002
(408)-946-6548
http://www.sfbbo.org/
chucao(AT)attbi.com
[ << | >> | ^^ ]
Subject: RE : VA Beach Gull
From: =?iso-8859-1?Q?Pierre-Andr=E9_CROCHET?= <crochet(AT)CEFE.CNRS-MOP.FR>
Date: 21 Mar 2003 2:47am
This is a multi-part message in MIME format.
----INCLUDING text/plain MIME SECTION----
Hi all,
=20
A very short one : yes, there are statistical differences in several =
characters of the wing tip pattern between various populations of Yellow =
Legged Gulls, including differences between Cantabrican and both =
Mediterranean and Southern Atlantic Iberian populations. Yes, there are =
some morphological characters of Cantabrican gulls which are similar to =
argenteus characters (amount of head streaking in winter, some =
morphometric characters). NO, Cantabrican gulls are not similar to =
argenteus in wing tip pattern, NO, they are not more similar overall to =
argenteus than to michahellis (in fact, when seen side by side, =
michahellis and Cantabricans are extremely similar except in winter for =
the most streaked individuals of Cantabricans, and an argenteus among =
them is really easy to spot: own experience on the Basque Country coast) =
and NO they can't be classified as "Herring Gulls". Don't trust the =
"literature" too much.=20
=20
The paper with these results by Pons et al. is in revision. We hope to =
have it published soon.
=20
And last (but this is more personal) NO I don't see how the VA Bach =
Gull could be a Cantabrican, or any, YLG.=20
=20
Hope this help,
=20
Pierre-Andr=E9
=20
Pierre-Andr=E9 Crochet
CEFE-CNRS
1919, route de Mende
34293 Montpellier cedex 5
France
tel: + 33 6 07 32 60 75
fax: + 33 4 67 41 21 38
crochet(AT)cefe.cnrs-mop.fr
-----Message d'origine-----
De : Nick Rossiter [mailto:nrossiter(AT)SUPANET.COM]=20
Envoy=E9 : jeudi 20 mars 2003 21:30
=C0 : BIRDWG01(AT)listserv.arizona.edu
Objet : [BIRDWG01] VA Beach Gull
=20
I'm not sure that everyone has looked at the cantabricans on Martin =
Reid's web site at:
http://www.martinreid.com/mcanp06.html =
<http://www.martinreid.com/gullsp33.html>=20
=20
This page shows a range of typical cantabricans adults. The wingtips of =
these birds are not typical michahellis. True P9 and P10 are similar to =
those of Mediterranean michahellis (plenty of white) and hence to =
argenteus. But the middle primaries are different. In general these =
show less tendency to black on P4, more likelihood of a spot or a thin, =
broken band on P5 and a greater tendency to a marked pale grey indent =
into the solid black area of the wingtip.=20
=20
My own studies show a similar picture. See=20
http://www.nrossiter.supanet.com/ylg/cantylg.htm
for details.=20
=20
In addition the literature abounds with information on the =
argenteus-like features of cantabricans including an orange-red orbital =
ring and extensive head markings into spring. I will give more details =
if required but see Martin Garner & David Quinn, p.58-59 90(1-2), in =
their British Birds article from January-February 1997 for a start.=20
=20
I think to some extent we're into classification problems. I only regard =
cantabricans as an Atlantic Yellow-legged Gull in the broadest sense. It =
does not fit well with the atlantis from further south and I would not =
classify it as such. The clasification of cantabricans is very =
debatable. It could even be included under argenteus (after all some =
argentatus have yellow legs). I think Pierre's DNA studies have linked =
it with michahellis.=20
=20
Obviously M. Pons information on cantabricans would be very welcome but =
we can only go on the evidence in the public domain. Is there any chance =
of making some summary information available perhaps? That would be a =
great help.=20
=20
Best wishes ... Nick
=20
=20
=20
=20
=20
=20
=20
=20
=20
=20
=20
=20
=20
=20
Citing unpublsihed results does not realy advance the debate unless =
you're going to release some information for us to see and evaluate. Is =
Mr Pons prepared to do this?
=20
I'll call as evidence Martins Reid's site already mentioned in his =
message at:...=20
=20
=20
=20
This pattern is much more like a Herring Gull than michahellis. In =
Mediterranean michahellis you often get a spot on P4, always a broad =
solid band on P5 and a solid black triangle to the wing tip.=20
See Paul Isenmann's seminal paper at
http://www.nrossiter.supanet.com/ylg/isenmann.htm
and Garner & Quinn (1997).=20
=20
=20
=20
Also see Teyseedre's paper on cantabricans=20
=20
In reply to Martin's comments, cantabricans can show an orange-red =
orbital ring. Geographically cantabricans is sandwiched betweem Herring =
Gull (argenteus) in western France and Iberian atlantis in north-west =
Spain.=20
=20
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