ID-FRONTIERS for August 19-25, 2001

Messages are displayed in the order they were received.  Subject  From  Date   Time   Re: QRY: Comparability of shorebird wing measurements: live birds ...   David James    Mon, 20 Aug 2001   2:07am   Re: Baltic Gull   Martin Helin    Tue, 21 Aug 2001   1:30am   Re: Hawaiian Petrel split   Peter Pyle    Tue, 21 Aug 2001   11:42pm   Re: Hawaiian Petrel split   Martin Reid    Wed, 22 Aug 2001   5:59am   AOUCLC decisions   Andrew Kratter    Wed, 22 Aug 2001   7:32am   Juv. Plegadis Ibis   Brush Freeman    Wed, 22 Aug 2001   8:24am   Re: Juv. Plegadis Ibis   ian paulsen    Wed, 22 Aug 2001   10:22am   more on AOUCLC decisions   Andrew Kratter    Wed, 22 Aug 2001   12:22pm   Gulls: thoughts on a Texas dark-backed gull   Martin Reid    Thu, 23 Aug 2001   6:46am   Re: Gulls: thoughts on a Texas dark-backed gull   Norman D.van Swelm   Thu, 23 Aug 2001   5:26pm   Re: Gulls: thoughts on a Texas dark-backed gull   Martin Reid    Fri, 24 Aug 2001   6:44am

To use email addresses replace '(AT)' with '@'. This is done to confuse the spam 'bots.

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Subject: Re: QRY: Comparability of shorebird wing
         measurements: live birds ...
From: David James <dave-james(AT)BEYOND.NET.AU>
Date: 20 Aug 2001 2:07am

Jim & all,

I don't claim to be an expert in these matters (I have measured a lot of
skins, summarised a lot of published and unpublished measurements data from
live birds and skins, but have only rarely preparered skins or measured
live birds). I offer some personal experiences (rather than answers) that
seem relevant to your questions.

The most common measurement of wing-lenght in recent publised sets of
measurements is maximum chord taken from skins (e.g handbooks like BWP,
HANZAB use Max chord unless otherwise stated). Max chord is taken on the
folded wing from the bend in the wing (the wrist) to the tip of the longest
primary, with the wing flattened and straightened along a ruler (ie
straightened in 2 planes to give the maximum lenght) (yes, "chord" is a
misnomer in max chord, but it is entrenched in the literature) . Older
literature may use (minimum) chord (ie with the wing neither flattened nor
straightened, and some workers use flattened chord (flattened but not
straightened). Unfortunatley, many published mesurment sets do not include
methods. To my knowledge, many field workers use maximum chord rather than
min chord because variation in the 2 cambers adds an extra source of
uncontrolled variation in measurements (ie max chord is more repeatable
than either chord or flattened chord). However, with really large birds
that have heaps of camber (like eagles and cranes) the wing can't always be
flattened or straightened consistently, and different workers have tackeld
this problem in many different and ingenious (read inconsistent) ways.
Therefore, you need to know exactly how the measurements were taken before
you can start comparing fresh and dry wing measurements to allowing for
drying.

At some point I came to beleive that shrinkage was about 2-5%, but I'm not
sure where that idea came from.

A few years ago I  measured wings on a series  21 Black naped terns  from
Fiji at the Nat Mus of NZ.  I compared max chord measurments taken by the
collector, F.C Kinsky, on the freshly dead skins in  1972 with max chord
measurements taken by me in 1994 on dried skins. I know from other work
that Kinsky always took maximum chord on small to medium sized birds, just
as I do. The difference between fresh and dry measurements in the terns was
a mean of 4.6 mm or about 2%. probably most of this was due to shrinkage.
Even so, there is almost certainly a slight difference between the way
Kinsky took max chord and the way I take it, and it is not possible to say
exactly how much. The summary data are published in HANZAB 3.

Many modern artists make extensive use of photos of live birds for their
illustrations, which I think is shown in the dramatic imporvement of  the
depiction of structure in recent guides.

Wingspan can not be taken from study skins; usually the wings are dried and
stuck in the folded position and can't be straightened. Even if the wings
are dried out-stretched, they will not be stretched consistently.  I looked
at the relationship between wingspan and maximum chord on about 50 Nankeen
Kestrels collected in NSW, Australia (Aust. Mus.). The single collector
took wingspan on the freshly dead specimens and I took the max chord about
20-25 years later in the museum. Birds with similar max chords had
differnences of perhaps 20% in wingspan. The relationship was very poor,
because wingspan is not a measurement that can be taken with repeated
accuracy (if you stretch the two wingtips apart as hard as you can you get
an unrelistically enlarged measurement, but if you let the specimen relax a
little you won't get the same stretch on each bird or even on the same bird
twice [for this reason I think that taking wingspan on live birds either
risks dislocation or returns worthless data, and should not be
attempted]).  I can't vouch for other countries, but the wingspan data for
non-passerines of Aust. and NZ is based on data on museum specimen labels.
The data are scarce, very innacurate,  taken by different workers using
different techneques, and are very unreliable,  but they appear in lots of
field guides etc.  My point is that shrinkage is irrelevant to the quality
of wingspan data. Maybe there are exceptions, but I don't trust the
wingspan measurements in books, except as an approximate guide to size class.

Total length can't be taken on skins because the trunk skeleton is removed
and replaced with a stick.

A decade ago I looked thru hundreds of Pluvialis fulva skins in Australian
collections for possible P dominica skins. I found that the tertials were
drawn forward on many specimens of fulva giving them an attenuated primary
extension like that of live dominica, and concluded that primary extension
was not relaibale on study skins of pluvialis. I've not found this to be a
problem on other birds, but I haven't looked so critically at p extension
in other species.  Tail will also shrink on skins as they dry. The
relationship between the tip of the tail and the tip of the wing is
completley lost in the preparation of skins, when the trunk skeleton is
removed.

Toe measurments are pretty unreliable on skins because the toes rarely dry
in a straight position.

cheers
David James
PO BOX 5225
Townsville Mail Centre,
Qld 4810, Australia
___________________________


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Subject: Re: Baltic Gull
From: Martin Helin <Martin.Helin(AT)RISSASOLUTIONS.COM>
Date: 21 Aug 2001 1:30am

Below I am forwarding this comment from Martti Hario as comments from Finns
were requested. [Hario is a very experienced gull researcher and the author
of a book on gulls of the Baltic Sea area (published in 1986 in Finnish, the
same year as Grant's 1st edition was published).]

        Martin Helin

The mail of Brian Small made me curious about the possible novelties
discovered by Dutch workers in fuscus vs. intermedius separation. I'd like
to repeat the questions of Brian Small and pose them directly to Dutch
colleagues, since no one in Finland possesses vast knowledge on intermedius
variation. My own experiences mainly stem from the skin collections of the
80's (1986). I then adopted pretty much the same view as Jonsson does in his
write-up of 1998.

In both forms, the range of individual variation in adult post-breeding
moult is large. Jonsson (1998) claims "usually a marked difference in
appearance" in mid-August--mid-September: a combination of black mantle
(with at least 50% brownish-black scapulars), unmoulted inner primaries, and
white head "should be enough to identify a vagrant fuscus" during the period
in question.

In my experience, nominate fuscus, indeed, never starts the migration with
incomplete set of flight-feathers. Nominate fuscus is a true long-distance
migrant, either suspending the post-breeding wing moult upon departing
(usually at PP1-3), or shedding no primaries at all and migrating with old
feathers. However, these old feathers can either be fresh-looking
stepwise-moulted spring feathers or abraded feathers from previous autumn
moulted in the normal descendant manner. Primaries of the former category
are extremely difficult to distinguish from genuine new feathers from
July-August, at least in the field (their similar outlook stems from the
fact that PP1-3 are concealed by the tertials and thus less prone to
abrasion than remaining primaries). The term "unmoulted inner primaries" in
Jonsson 1998 possibly marks the latter category, the roughly one-year-old
primaries, not produced in stepwise moult. There is no way to separate these
fuscus-feathers from intermedius feathers by outlook, so the timing and
extent of the remigal moult remains the only clue.

By early September, the moult in intermedius has usually advanced beyond P3,
which normally marks the final stage of the post-breeding moult of fuscus in
August. Apparently, Dutch workers have revealed intermedius/graellsii
individuals that share the features of post-breeding adult fuscus, viz.
being white-headed in mid-September and having ceased the moult at P3 or
having not commenced it at all.

Of course, this is to be expected. These differences in moult only work at
the population level, not as diagnostic subspecific identification keys
working on every odd, lone individual. As Jonsson puts it: "...anyone
checking intermedius/graellsii...will, sooner or later, encounter a dark,
late moulting intermedius without spots on the head...".This means that only
certain individuals are identifiable for a certain period of their year
cycle. For some reason, Jonsson fails to give details on such late-moulting
intermedius individuals leaving the reader unaware of how to tell a typical
fuscus from an atypical intermedius.

Even this view may be changing currently, however. Nominate fuscus has
declined drastically over most of its range. This can set stage for changing
immature tactics as has been shown from culled Herring Gull populations in
England. With the diminishing number of mature adults the period of
immaturity of young gets shorter bringing them earlier to vacant breeding
territories (Coulson et al. 1982). One could further speculate that also
their plumage sequence, in a long run, might become more rapid (this topic
not adressed in Coulson et al.'s work) and the brownish plumage, manifesting
their submissive status within the colony (saving them from adult
aggressions), will be retained for a shorter period than previously? Or, in
fuscus, the first prospecting migration to north may take place earlier?

However, no changing tactics in adult post-breeding moult of fuscus has been
discovered so far (no earlier start and further advancement of moult as a
result of surplus time caused by failing reproduction, not at least in the
Gulf of Finland). If such novelties have been detected among intermedius it
would be good to know.

Martti Hario
Helsinki, Finland

-----Original Message-----
From: Brian Small [mailto:BrianJSmall(AT)AOL.COM]

Peter Adriaens has stated that the Dutch are of the opinion that fuscus
overlaps with intermedius in every respect (moult, structure plumage), and
as
such it is not possible to separate the two in the field.  This of course is

contrary to the main article by Lars Jonsson in Birding World Vol.11 number
8, in which he puts forward the means by which you should be able to
identify
fuscus at certain times of the year.

I have heard that the Dutch have this opinion before and ask the following
questions.

Are they saying that Lars Jonsson is totally wrong in his article, for all
ages? Or are there any features which can be used?

Secondly, on what observations are they basing this comment?  Do the Finns
agree with them?

I am very interested to know.

Brian Small
Suffolk, UK


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Subject: Re: Hawaiian Petrel split
From: Peter Pyle <ppyle(AT)PRBO.ORG>
Date: 21 Aug 2001 11:42pm

Thanks to Doug for sharing this news. I am a bit disappointed in the
split of
Hawaiian and Galapogos petrels, however, as they are virtually
impossible to
differentiate at sea. There is a currently a lively debate about which
one is
showing up increasingly in California. My guess has been Galapogos since
that
population is increasing (after eradication of goats and rats from
breeding
islands in the early 1990's) while the Hawaiian population remains small
and
static. But I understand that at-sea distributional evidence favors
Hawaiian.
We can't collect one so we may never know.

I agree completely with Doug's last sentence. In this regard, does
anyone know
where the Hawaiian vs. Galapogos petrel information has been
published(?) as
I'd like to see it. The one paper I've seen (I believe published in
Emu(?)
many years ago) was not conclusive regarding morphological and plumage
differences.

We are in an era of accelerated splitting, in part due to increased
genetic
evidence. While the recent DNA work is very valuable and interesting, it
seems
a bit early to me to be using it to upend our species definitions. I
would
guess we'd be better off waiting a decade or so for all of the genetic
information to be gathered and synthesized in an overall context before
splitting
more species that cannot be identified in the field.

Peter Pyle

"H. Douglas Pratt" wrote:

> Dear Birders:
>
>         It's official!  At their meeting recently in Seattle, the AOU
> Check-list Committee voted to recognize Pterodroma sandwichensis as a
> species separate from Pt. phaeopygia of Galapagos.  This split has been in
> the works for a long time, but the supporting data have really piled up
> now (behavior, DNA, anatomy, etc.).  According to Van Remsen, Newell's
> Shearwater may well be split when comparable data are available to support
> it.  This has some bearing on my earlier comments about Hawaiian Stilt.
> The AOU CLC is usually very conservative in making changes of this type
> (some recent rather rash decisions notwithstanding).  They have not yet
> voted on splitting 'Elepaio, and I suspect they will await publication of
> recent DNA work coming out of Becky Cann's and Rob Fleischer's labs.
> (According to Rob, preliminary results seem to show a very ancient split
> between at least 2 of the 3 potential species.)  One thing they absolutely
> insist on is that information must be published.  "If it hasn't been
> published, it hasn't been done" as the old saying goes.
>
> Doug
>
> ********************
> H. Douglas Pratt
> 964 Highland Park Drive
> Baton Rouge LA 70808
> (225) 757-9441  FAX (225) 388-3075
>
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Subject: Re: Hawaiian Petrel split
From: Martin Reid <upupa(AT)AIRMAIL.NET>
Date: 22 Aug 2001 5:59am

Dear all,
My thanks to Peter Pyle and Doug Pratt for this snippet, but can anyone
tell me/us where to read about ALL the decisions made by the AOU Checklist
Committee last week? - I've browsed the AOU web site, but could not find
any details there - thanks.
Martin

Martin Reid
Fort Worth, Texas
upupa(AT)airmail.net
http://www.martinreid.com  or  http://www.cyberramp.net/~upupa


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Subject: AOUCLC decisions
From: Andrew Kratter <kratter(AT)FLMNH.UFL.EDU>
Date: 22 Aug 2001 7:32am

Frontiers-
AOU CLC decisions are not official until they are published.  The next
supplement will be in the July 2002 Auk.  Therefore, Dark-rumped Petrel (P.
phaeopygia) still includes the Hawaiian population (sandwichensis).

Andy Kratter
AOU Committee on Classification and Nomenclature (aka AOU Check-list Committee)
Dr. Andrew Kratter, Collections Manager- Ornithology
Florida Museum of Natural History
PO Box 117800
University of Florida
Gainesville, FL 32611 USA
Ph. (352) 392-3293
Fax (352) 846-0287
http://www.flmnh.ufl.edu/


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Subject: Juv. Plegadis Ibis
From: Brush Freeman <brush(AT)ONR.COM>
Date: 22 Aug 2001 8:24am

   Sometime back there was a question to this list regarding a possible
feature on first summer/fall Glossy Ibis that maybe indicative of the
species and a useful tool in separating those young birds from similarly
aged White-faced Ibis. I don't believe I ever saw a satisfactory answer to
that question and find nothing helpful in the archives.
   This feature pertains to the horizontally banded throat as illustrated
for first fall Glossy Ibis in the 3rd edition of NGS.  I know that this
throat pattern does exist on young Glossy Ibis but I am uncertain as to how
definitive it is as a useful field mark for separating the two species at
this age.  As the mix of the two species becomes more apparent in the south
and west, an knowledgeable answer on this would be most helpful as we
struggle with an otherwise tough identification problem.  Both species
breed now in numbers on the Texas gulf coast and often in mixed colonies so
this ID dilemma is a topic of much conversation.  Perhaps someone who has
worked with both species at this age, where  breeding ranges overlap, could
provide some much needed insight.

Many Thanks,
Brush Freeman
TBRC
Utley, Texas
Brush(AT)onr.com


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Subject: Re: Juv. Plegadis Ibis
From: ian paulsen <ipaulsen(AT)LINKNET.KITSAP.LIB.WA.US>
Date: 22 Aug 2001 10:22am

HI ALL:
 Try reading this article:
  Range expansion of the Glossy Ibis in North America. Michael Patten and
Greg Lasley. North American Birds 54:241-247, 2000. See pages 244-45 for
identification notes.
sincerely

Ian Paulsen
Bainbridge Is., WA, USA
ipaulsen(AT)linknet.kitsap.lib.wa.us
A.K.A.: "Birdbooker"
"Rallidae all the way"


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Subject: more on AOUCLC decisions
From: Andrew Kratter <kratter(AT)FLMNH.UFL.EDU>
Date: 22 Aug 2001 12:22pm

Frontiers-
Evidence considered by the committee in recent discussions on
Pterodroma  phaeopygia/sandwichensis are included in:
Browne, R. A. et al.  1997.  Condor 98:812-815.
Pratt and Pratt.  200l.  SAB on Hawaii
Sibley and Monroe 1993.  Supplement
Simons, T. R.  1985.  Condor 87:229-245.  Re Hawaiian birds
Simons and Hodges.  1998.  Birds on North America 345
Tompkins, R. J., and B. J. Milne.  1991.  Notornis 38: 1-35..

These references included data on morphology (phaeopygia larger), egg size
(sandwichensis larger), plumage (phaeopygia sometimes with black streaks on
forehead), vocal differences, breeding season (phaeopygia protracted,
sandwichensis contracted), non-breeding distribution (possibility sympatric).

The current crop of eight committee members in the AOU CLC all lean towards
defining species using the Biological Species Concept, so we make species
levels decisions based on reproductive isolation.  Molecular distances,
however measured, only give a historical account of divergence and do not
indicate current (unless populations are intensively sampled in sites of
sympatry) or potential reproductive isolation.  As I mentioned on the
ListServe previously, reproductive isolation arises arbitrarily on a
continuum of  molecular divergence.  However, the greater the divergence
the more likely the taxa are reproductively isolated.   Identification in
the field is not a criterion for assessing reproductive isolation (e.g.,
the one species of YR Warbler with easily identified pure types vs the two
species of "Traill's Flycatchers, which are difficult even in the hand),
although it certainly makes matters easier.

When our decision is made official (in the July 2002 Auk), the changes will
be incorporated into our list on the web
(http://www.aou.org/aou/birdlist.html).  Hopefully the contents of the Auk
will soon be accessible on the web (via PDF files), like some other
scientific journals.  In the mean time, Birding and other bird-watching
journals often have articles that discuss these changes.

By the way, our membership in the AOU-CLC is completely voluntary.

Andy Kratter
AOU Committee on Classification and Nomenclature (aka AOU Check-list
Committee)

Dr. Andrew Kratter, Collections Manager- Ornithology
Florida Museum of Natural History
PO Box 117800
University of Florida
Gainesville, FL 32611 USA
Ph. (352) 392-3293
Fax (352) 846-0287
http://www.flmnh.ufl.edu/


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Subject: Gulls: thoughts on a Texas dark-backed gull
From: Martin Reid <upupa(AT)AIRMAIL.NET>
Date: 23 Aug 2001 6:46am

Dear all,
Given the recent Larid themes, I'll offer some thoughts about the unusual
dark-backed large gull(s) seen in Texas these past few winters, and seek
some feedback:
This concerns this/these bird(s):
http://www.martinreid.com/gullsp04.html - I would encourage those
interested to go to the first link therein, where the latest photos are
displayed, plus links to other relevant comparative images.
I've given this bird a great deal of thought, and I am persuaded that the
best explanation would be a taimyrensis/vegae(birulai) hybrid - why?:-
It clearly does not match what we thus-far know about the darker-mantled
taxa (graellsii, intermedius, fuscus, heuglini, taimyrensis).
Equally it does not come close to matching the darker forms of HERG (vegae,
argentatus) or YLGU (atlantis).
It does seem in many ways to be intermediate between HERG and the
darker-mantled taxa, so why not a smith HERG X graellsii, as this would
seem to be the geographically-closest hybrid option, ?
- well, for a start, no such hybrid has ever been confirmed in North
America (please correct me if I'm wrong) - although there have been a
handful of contenders photographed.  Even in Europe, where the breeding
overlap and recent increases in LBBG numbers seem to present ample
opportunity, such hybrids are relatively rare.
- also, there are three anomolies for a HERG (smith/argentatus/argenteus) x
LBBG (graellsii/intermedius): - all the donor forms are pale-eyed, yet the
mystery bird is darkish-eyed (in the latest photos, they are strikingly
darkish); all the donor forms typically have the tail falling between P6
and P7 - with most of them being closer to P7, yet the mystery bird has its
tail falling just short of P6; typical examples of all the donor species
would have finished their P-molt by mid-January (but LBBGs wintering in
southern US have a much later molt; where do they breed?), yet the mystery
bird has P10 a little over half-grown.
So, looking for another explanation, we come to taimXvegae:
This is known to be a very large hybrid swarm, which, despite coming from a
small breeding zone (taim. only breed in a limited area at the base of the
Taimyr Pen.) significantly outnumber pure taim. along the western Pacific
(i.e. closer to our region).
Many vegae are very dark-eyed (but what about birulai, the race doing the
interbreeding with taim?).
Vegae is regularly still growing P10 in January  (and taim is an even later
molter).
Photos from Japan -
http://isweb15.infoseek.co.jp/animal/larus/gullidentifi_.htm (but note that
many of the birds listed under "Heuglin's Gull" are probably taimXvegae
hybrids; pure taim is rare/scarce in Japan - Jon King, pers comm.) show
that this hybrid form often has the tail falling below P6. My personal
experience with heuglini in Bahrain (including the larger, paler birds that
may be hybrids) shows that this form resembles fuscus in its tail/wing
position, with the tail tip often falling under or short of P6 (I have many
photos showing this) - thus if taimyrensis is a derivative of heuglini, it
too may have this propensity for the tail to fall under P6.  Vegae averages
longer-winged than smith, but many smith (presumably from the northernmost
breeding colonies) can look just as long-winged.

So, we have a common hybrid form (taimXvegae) that answers all the
anomolies of the rarer "LBBG X other HERG" possibility, plus one of North
America's first documented Vega Gulls outside Alaska
(http://www.martinreid.com/vegup05.html) was found at exactly the same
location in Texas....to me it seems a reasonable conclusion (but not
provable, of course).
I'd be very interested to hear some response to this suggestion, especially
if I have misrepresented any of the data - thanks.
Martin

Martin Reid
Fort Worth, Texas
upupa(AT)airmail.net
http://www.martinreid.com  or  http://www.cyberramp.net/~upupa


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Subject: Re: Gulls: thoughts on a Texas dark-backed gull
From: "Norman D.van Swelm" <Norman.vanswelm(AT)WXS.NL>
Date: 23 Aug 2001 5:26pm

Martin Reid wrote, among other things:>Many vegae are very dark-eyed (but
what about birulai, the race doing the
>interbreeding with taim?).
>I'd be very interested to hear some response to this suggestion<

Martin's website shows a dark mantled bird from last year with very pale
eyes and a dark mantled bird from this year with very dark eyes! Whatever
these birds may be, I have never heard of gulls' eyes becoming dark after
they have been pale! So I would conclude that these are two different birds.
They are definitely not graellsii. They certainly look like taimyrensis but
perhaps hybrids of all American stock look like this as well. When you think
of it colour ringing/banding may provide all the answers in the end.
Norman


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Subject: Re: Gulls: thoughts on a Texas dark-backed gull
From: Martin Reid <upupa(AT)AIRMAIL.NET>
Date: 24 Aug 2001 6:44am

Dear Norman/all,
You highlight a puzzling difference between the two occurrences - but has
anyone actually studied ringed individuals to determine this?  In Texas we
had a a PRESUMED returning LBBG for 10+ years, and the changes in bill
color were quite revealing: http://www.martinreid.com/lbbg0inx.html - are
there also some minor changes in apparent eye color - ?
Anyway, please look at the last Corpus gull again
http://www.martinreid.com/gullspx4.html
and compare it to the three gulls from Japan below (listed as full taim.,
but I suspect all are hybrids or backcrosses with birulai) - especially
note the very short tails, molt stage, eye color, head/nape streaking,
legs, etc.:
http://isweb15.infoseek.co.jp/animal/larus/taim_ad001230/taim_ad001230_sa.html
http://203.174.72.112/vegae/taimy010105adS/taimad01_1_5S.html
http://203.174.72.111/vegae/taim4w010303/taim4w01_3_3.html
- if someone can point me to pics of any other gulls that look as/more
similar to the Corpus bird(s) - PLEASE do so - thanks!
Cheers,
Martin

At 8/24/2001 02:21 AM +0200, you wrote:

>Martin Reid wrote, among other things:>Many vegae are very dark-eyed (but
>what about birulai, the race doing the
> >interbreeding with taim?).
> >I'd be very interested to hear some response to this suggestion<
>
>Martin's website shows a dark mantled bird from last year with very pale
>eyes and a dark mantled bird from this year with very dark eyes! Whatever
>these birds may be, I have never heard of gulls' eyes becoming dark after
>they have been pale! So I would conclude that these are two different birds.
>They are definitely not graellsii. They certainly look like taimyrensis but
>perhaps hybrids of all American stock look like this as well. When you think
>of it colour ringing/banding may provide all the answers in the end.
>Norman

Martin Reid
Fort Worth, Texas
upupa(AT)airmail.net
http://www.martinreid.com  or  http://www.cyberramp.net/~upupa