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Subject: Florida Little Gull - the final chapter....
From: Martin Reid <upupa(AT)AIRMAIL.NET>
Date: 25 Feb 2001 3:48pm
Dear all,
Alan Worrmington has kindly made availible three more photos of the
now-infamous Florida Little Gull:
http://www.martinreid.com/ligup01.html
Regards,
Martin
Martin Reid
upupa(AT)airmail.net
http://www.martinreid.com or http://www.cyberramp.net/~upupa
[ << | >> | ^^ ]
Subject: Elegant Terns in Europe??
From: Laurent Raty <l_raty(AT)HOTMAIL.COM>
Date: 27 Feb 2001 10:16am
Hi all,
Following a request to review of a record of an orange-billed tern in
Belgium, I started recently a discussion with some friends, about the status
and identification of Elegant Tern in Europe. We did not reach a consensus
and I would be interested in additional info about several points, as well
as in the advice of others. Some might argue that my advice is biased (I did
not see the Belgian bird ;-). However, as I was trying to gather information
about the species, all concurred to reinforce my views.
The text is rather long, sorry, but it's still winter and it's not about
gulls.
(It's about probabilities, which is perhaps not better ;-)
(Note: I don't have direct easy access to American literature, which means
that my information could be fragmentary on some aspects. Please, correct me
if you find any imprecise of false statement.)
* RANGE OF ELEGANT TERN
Elegant Tern breeds in a restricted range on the Pacific side of N America,
from S CA to C Baja California and from Gulf of California to Nayarit (with
90% or more of the total known breeding population possibly in a single
colony on Isla Rasa in the Gulf of California).
It regularly wanders north to N CA as a post-breeding visitor (midsummer
through fall). With recent El Nino events, these northern incursions seem to
have increased. It was first recorded in OR in 1983 but is now of annual
occurrence. Irruption events took place in 1983 and 1990, with birds
reaching as far north as BC - in WA, Elegant is currently described as an
"irregular fall migrant on coast (usually absent but common during El Nino
years)"; it is considered an exceptional visitor in Canada. I could not find
any record from AK.
Elegant migrates south, to winter along the Pacific coasts of America,
mainly in Peru and N Chile, but a few birds can remain north, as far as
California, and others reach as far south as C Chile. I could not trace any
record from S Chile - all maps I have seen showed a winter range extending S
at most to the latitude of Santiago de Chili (i.e., still more than 2,000 km
N of the Strait of Magellan). The species is unrecorded from Argentina.
* HABITAT AND MIGRATION HABITS
As far as I can see, Elegant Tern is an almost strictly coastal species.
In CA, according to Joe Morlan's county lists, it is a normal visitor to all
coastal counties (i.e., including the counties adjacent to the San Francisco
Bay) but, among the 38 counties that are not directly adjacent to the sea,
only 2 have the species on their list - Riverside and Imperial - and it is
considered to be a rarity there. It is either unrecorded or an extreme rare
vagrant to any State not adjacent to the Pacific Ocean, even as close to its
normal range as AZ. Extralimital inland occurrences I could trace occurred
in AZ (3 accepted records - 4 birds) and TX (1 accepted inland sight
record) - that's all.
Similarly, my impression is also that Elegant is not at all a highly pelagic
species. According to Del Hoyo et al. (HBW 3), "migrants feed in harbours,
estuaries, salt-ponds and lagoons", "non-breeders feed in lagoons and bay,
avoiding rough waters". According to all maps I have seen, Elegant's winter
range follows strictly the coasts. Harold Holt (A Birder's guide to Southern
California) lists the species as "hard to miss" along the coasts at the
right season, but it is not even supposed to be a possibility on open ocean
well offshore. Silcock (http://sidney.heartland.net/silcock/) provides an
annotated checklist of the Birds of the Pacific Region (defined as: "the
Pacific Ocean to within 200 miles of major land masses and south to 60S",
"northward off North America and westward south of the Aleutian Is"; check
the site for more detail). Within this region are Guadalupe, Revillagigedo,
Clipperton, Coco Is. and the Galapagos (where the ornithological pressure
can not be assumed to be low!), all of which could arguably be reached
easily by an Elegant, providing this one showed only a slight interest in
wandering above open waters. But, apparently, Elegant never reached ANY of
these. In the whole region, Silcock lists only one (rather extraordinary)
record, from Johnston Atoll (roughly 15 degrees W of Hawaii). Even if this
sighting seems to show that Elegant is physically able to cross oceans,
being the only record, it also obviously shows that Elegant won't do this
willingly.
Based on this, it seems clear that either a few 10s of miles over land, or
200 miles over open water from an area *where Elegant is common*, are enough
to make it an extremely rare and accidental species.
* COASTAL RECORDS ON THE ATLANTIC SIDE OF AMERICA
To my knowledge, there are only two accepted records on the Atlantic side of
North America:
1) 25 Jul 1889, Corpus Christi, Nueces Co., TX: specimen, BMNH
No.91-10-20-92.
2) 20 Jun 1985, Chincoteague NWR, VA: adult photographed.
(Notes:
a. There is a second record from TX:
23 Dec 1985, Lake Balmorhea, Reeves Co., TX: photographed, TPRF No. 397.
But, as Balmorhea lies in the west corner of the state, close to New Mexico
and roughly halfway between the Gulf of Mexico and the Gulf of California,
this record can't be assigned to the "Atlantic side of N America";
b. Astonishingly, the VA sighting is not mentioned in Del Hoyo et al. (HBW
3), while the species is explicitly said to be accidental in TX.)
There is/are one/two additional recent record(s) from Florida, not yet
assessed by the Florida RC (sorry, I don't have the exact dates for the
second record):
3) 3 Oct - 22 Nov 1999, Honeymoon Island State Recreation Area, FL: 1
adult;
3b) Late fall - early winter 2000-01, Fort DeSoto, FL: 1 adult.
Assuming these refer to a returning individual is obviously tempting.
According to Boesman (Dutch Biding 14(5):161-169), there is also one sight
record on the Caribbean coast of Costa Rica - but I could not find more info
about this bird.
I could not trace any record from Atlantic South America.
* OCCURRENCES IN EUROPE
Currently accepted records of Elegant Terns from Europe are as follows:
1) 1974 - 1984 at least, Banc d'Arguin, Arcachon, Gironde, France: 1
individual, not
annually; paired with Sandwich Tern - initially ID'd as Lesser Crested Tern;
2) 22 Jun - 3 Jul 1982, Greencastle Point, Carlingford, Lough, Down,
Northern Ireland, UK, 1 individual;
2b) 1 Aug 1982, Ballymacoda, Co. Cork, Ireland, 1 individual, considered the
same as (2);
3) 1984, Banc d'Arguin, Arcachon, Gironde, France; second adult (!!!) in
the
same colony as (1), both birds paired with a Sandwich Tern; as previous
bird, initially ID'd as LCT;
3b) 1985-1993 at least, Banc d'Arguin, Arcachon, Gironde, France: still one
individual; likely to be one of the 1984 birds, but it is unclear which
one - caught, color-ringed and finally ID'd as Elegant in Jun 1987;
3c) 9, 10 & 28 Aug 1985, Sables d'Olonne, Vendee, France: 1 adult,
considered probably one of the 2 previous birds;
3d) ?? Aug 1991, St-Nazaire, Loire Atlantique, France: 1 adult, definitely
the color-ringed bird from Banc d'Arguin (3b).
4) 24 - 30 Apr 1993, Llobregat Delta, Barcelona, Spain: 1 adult,
photographed.
5) 1995-96 at least, Ile aux Moutons, Archipel de Molene, Finistere,
France:
1 individual, photographed in a Sandwich Tern colony, considered possibly
same as (1) or (3);
Currently awaiting acceptance:
6) 12 Jun & 15 Jul 1988, Zeebrugge, West-Vlaanderen, Belgium: 1 adult,
photographed - originally rejected because of a possible hybrid origin but
currently under review and could be found acceptable as Elegant (or, at
least, not less acceptable than other European records);
7) 8 - 21 Jul 1999, Lady's Island, Co. Wexford, Ireland: 1 adult in winter
plumage;
8) 30 May - 11 Jun 2000, Langi, Esbjerg, Vestjylland, Denmark: 1 adult male
in summer plumage, displaying in a Sandwich Tern colony.
There is a number of additional claims/sightings from France for which I
don't know if they were submitted/accepted. What I traced (certainly not
exhaustive):
+ 2 Jun 1996, Loctudy, Finistere;
+ 6 Aug - 1 Sep 1996, Sables d'Olonne, Vendee;
+ 13 May 2000, Banc d'Arguin, Arcachon.
Situation is further complicated by an additional Elegant-like bird trapped
at Banc d'Arguin in 1987, for which a hybrid origin could not be discarded
but that is considered very probably Elegant anyway. This bird was seen at
Banc d'Arguin until 1996 at least.
Rejected record:
1) 1 Aug 1997, Saline di Siracusa, Siracusa, Sicily, Italy: 1 adult
(documentation and observation duration considered insufficient to allow a
correct determination).
* LIKELIHOOD OF THE EUROPEAN OCCURRENCES
Absolutely NO other species with a distribution range similar to that of
Elegant Tern has ever reached the Western Palearctic.
It has been argued (a.o., Gutierrez, Dutch Birding 20(1):1-5) that "other
Pacific American species have occurred in Europe as well". Of course, this
is true. However, these species (Aleutian Tern, Parakeet Auklet, Crested
Auklet, Ancient Murrelet, Tufted Puffin and Glaucous-winged Gull) all breed
much farther north than Elegant. All are extreme vagrants to the WP, with
usually only 1 (at most 2) sightings in the last 200 years and, actually,
there is no evidence that any of them reached Europe more than once.
With the exception of GWGU, all are known to be highly pelagic in winter and
all are likely to have followed polar or near-polar routes to reach us.
Sightings of GWGU are perhaps a bit more tricky to explain as, at first
glance, this species is less pelagic than others, but it is nevertheless
much more prone to cross open water than Elegant Tern (it is apparently a
normal winter visitor to Hawaii!), it is much less likely to be stopped by
land than Elegant Tern, it has been recorded on several occasions as far
east as the Great Lakes and, again, the two WP records could well concern
the same single individual.
Elegant would be extremely unlikely to take a northerly route to reach
Europe. If it does not reach Tierra Del Fuego in the south, its normal range
will not allow it to change of ocean without crossing land, which is
something that this typically coastal bird will certainly not be prone to
do. The best chance I see for an Elegant ending up on the Atlantic side of
America would therefore be a storm-drifted bird, pushed over land in winter
somewhere in Central America, which is likely what happened to the Costa
Rican bird cited above. Note that, once it has crossed, the bird is likely
to stay on the east side of the continent, so it's not necessary that the
storm occurred immediately before the sighting. Anyway: this way, the bird
would reach the Caribbean Sea. If it acts normally, it will head north in
spring, along coasts, to appear somewhere in the Gulf of Mexico or, at best,
along the southern east coast. This apparently already occurred and would
account for the TX, VA and FL reports but, in view of the extremely low
number of sightings (one-two per century!?), it is certainly not a regular
event. And, to reach Europe, there's still the Atlantic to cross...
Also intriguing, is the fact that all European records of Elegant Tern are
well north of Elegant's breeding range, at latitudes at which, in America,
it is at best an uncommon post-breeding visitor, at worse a very rare
vagrant or an unrecorded species (Northern Ireland and Denmark both lie as
far north as southern AK). I know the climate can be different in different
oceans, but all other Pacific American species sighted in the WP were at
latitudes compatible with their American range. Why would Elegant Tern be
the exception? And what would a West Coast birder think about an Elegant
displaying in a colony at a latitude at which Arctic Terns, Kittiwakes and
Fulmars are all breeding?
For all the above reasons, I feel that each of the European Elegant Tern
sightings, even taken separately, would already be a totally improbable
event - each of them perhaps even less likely than an Aleutian Tern.
Now, what is the probability to have one Elegant breeding in a Sandwich Tern
colony in France for 10 years, before BEING JOINED by a second bird, and to
see both birds form hybrid pairs with Sandwich on that year!?
Some of the European sightings are likely (and certainly, in some cases) due
to relocated birds, which could limit the number of individuals involved,
but (1) in France, there were definitely 2 birds; (2) I have no data at hand
for Elegant but, according to Cramp et al. (BWP IV), the oldest recorded
Sandwich Tern was 23 years old - I guess that survival in Elegant is likely
to be similar - European sightings cover a period that is longer than that
and, therefore, the first bird at least is most likely dead for some years
now; (3) is it really likely that the same bird could spend spring in Spain
on one year, in Denmark on another year, especially as, according to
Gutierrez, the Sandwich Terns with which it associated in Spain were
presumably not part of the Atlantic population, and the Spanish bird's
description fitted better a female, while the Danish bird was a displaying
male?
In Europe, we have now reached a situation in which a "proven" pattern of
occurrence of Elegant Tern serves as an argument to accept some birds. I
feel this is a completely wrong way to analyse what happens. If Elegant Tern
reached us, it should be so rare that NO pattern should emerge. Every
additional sighting actually increases the uncertainty, as the accidental
character of all previous occurrences becomes less and less acceptable: the
existence of a pattern is, therefore, the best proof that there is a problem
somewhere.
* SO, WHAT IS HAPPENING?
Well, I don't have an all-built definite answer. I agree that (at least,
some of the) European Elegant Terns match quite closely American birds in
appearance.
Obviously, we have three possibilities:
(1) My reasoning is basically wrong. Elegant Terns do cross continents, are
overlooked inland, are overlooked on the east coast, do cross oceans and can
spend spring at the latitude of Alaska... Or, alternately, Elegant Terns do
reach the Strait of Magellan, are overlooked in southern Chile, are
overlooked in Argentina and in Brazil, do cross oceans and can spend spring
at the latitude of Alaska...
These are of course possibilities, but I would prefer to see evidences that,
at least, some of these assumptions are true. I'm ready to change my mind
but, based on the information I have at hand, I feel this explanation is
highly unsatisfactory.
(2) Del Hoyo et al. (HBW 3) are correct when they state: "Odd records from
Netherlands, Ireland, Spain and France (including hybridization with T.
sandvicensis), but provenance of such birds in question, as species
virtually unrecorded anywhere in North America away from Pacific coast;
probably attributable to escapes from shipments of exotic seabirds from
wintering grounds in W South America".
(Note: the record from Netherlands cited here is probably an erroneous
reference to the Belgian record, that was published in Dutch, in a Dutch
magazine, without the word "Belgium" in the title.)
(3) We have a big identification problem and some (all?) of the European
sightings are NOT Elegant Terns, but something else that mimics Elegant's
appearance - either a type hybrid or a non-described, (extremely) rare
variation in an Old World species.
These three explanations are all plausible to some extent and could even all
play a role simultaneously in the saga of sightings described above.
Whatever the answer, my opinion is that the current situation is (at the
very least) unclear and can not be explained. I feel therefore that there is
a real doubt about the validity of all European sightings of Elegant, and my
doubt will be growing with each additional accepted record. In such a case,
I'm afraid, the only reasonable way to treat the problem would be to review
and reject ALL accepted sightings and to stop accepting additional ones, at
least until we have a better idea about the actual origin or identity of the
birds involved.
Furthermore, as the problem is global, I feel that no particular European
record of Elegant, even extremely well documented, should be considered
alone (except, perhaps, if the bird wears a Californian or Mexican ring).
As long as we won't have a satisfactory global answer explaining ALL
sightings, a doubt will remain about all of them.
Reactions are welcomed (and expected ;-).
* FURTHER QUESTIONS
I would be interested in answers to the following questions:
- Are there any other records of Elegant Tern on the Atlantic side of USA
that I did not mention?
- Are there any further records from the Caribbean Sea or any further info
about the Costa Rican sighting? Are such Central American records submitted
to and assessed by any particular instance (esp., when the species is not a
vagrant to the coutry)?
- I know some people on this list have experience with coastal and pelagic
birding in Chile: do you know any record of Elegant closer to the Strait of
Magellan than what I stated?
- When pelagic trips are organised off western USA (a.o., Monterey), Elegant
regularly stands on the lists: are these birds seen well offshore or only
close to the continent?
- This may be a basic question (sorry if it's the case), but has Lesser
Crested been considered as a possibility when identifying the east-coast
Elegant Terns?
- I found a reference to online pics of the FL bird, but without a URL and
I failed to find them using the classical search engines: does anybody know?
- Is there any known information about the temperature requirements of
Elegant? A study linking sea water temperature off N CA, OR, WA and BC to
the presence or absence of Elegant, during normal years, versus major El
Nino events (1983, 1990) could perhaps enlighten us?
- If there are any French birders out there, I would be interested to know
in what the presumed hybrid ringed in 1987 at Banc d'Arguin differed from
the assumed pure birds seen on the island? Is the sex of any of the birds
known?
Kind regards and good birding,
Laurent
Laurent Raty,
Brussels, Belgium
[ << | >> | ^^ ]
Subject: Re: Elegant Terns in Europe??
From: Clay Taylor <CTaylor(AT)WORLDNET.ATT.NET>
Date: 27 Feb 2001 12:25pm
Hello All -
On the subject of the Eastern US occurrences of Elegant Tern, the
Florida bird found in October 1999 north of Clearwater, FL came on the heels
of a weak hurricane that (to the best of my recollection) crossed the Gulf
of Mexico from the Yucatan Peninsula area and proceeded to disintegrate over
Florida. It stayed for at least six weeks, and it would make sense that
the 2000 bird could be the same individual.
On another front, I saw multiple Elegant Terns two years running at
Waterloo, Trinidad, West Indies. I was leading a birding tour in March,
1998, looking for a flamingo that had been seen there the week before. At
the site were multiple Large-billed Terns and Royal Terns sitting on
pilings, and I casually announced to the group that there was an Elegant
Tern there, as well. Our local guide was Courtenay Rooks, and he tried to
tell me that there were only Royals in Trinidad, but I showed him the bird
through my spotting scope. He looked it up in Harrison's "Seabirds",
checked the scope again, and did a little celebration dance for a new life
bird in Trinidad. The following year, we saw three in the same place, as
well as a Gull-billed Tern in addition to the usual suspects.
When the article on Elegant Terns appeared in Birding Magazine, it did
not list any records for the Atlantic coast of South America, so I e-mailed
my sightings to the authors of the article. They responded that they, for
the purposes of the article, did not review any sightings or data that were
significantly outside the ABA area.
We never photographed the birds (they were a few hundred yards away),
and I have never followed up with Courtenay as to their status on the
Trinidad list (note - not listed by ffrench in his guide to the birds of
T&T). If you are interested, I can supply you with Cortenay's e-address.
Clay Taylor
Moodus, CT
ctaylor(AT)swarovskioptik.com
----- Original Message -----
From: "Laurent Raty" <l_raty(AT)HOTMAIL.COM>
To: <BIRDWG01(AT)LISTSERV.ARIZONA.EDU>
Sent: Tuesday, February 27, 2001 12:12 PM
Subject: [BIRDWG01] Elegant Terns in Europe??
> Hi all,
>
> Following a request to review of a record of an orange-billed tern in
> Belgium, I started recently a discussion with some friends, about the
status
> and identification of Elegant Tern in Europe. We did not reach a consensus
> and I would be interested in additional info about several points, as well
> as in the advice of others. Some might argue that my advice is biased (I
did
> not see the Belgian bird ;-). However, as I was trying to gather
information
> about the species, all concurred to reinforce my views.
>
> The text is rather long, sorry, but it's still winter and it's not about
> gulls.
> (It's about probabilities, which is perhaps not better ;-)
>
> (Note: I don't have direct easy access to American literature, which means
> that my information could be fragmentary on some aspects. Please, correct
me
> if you find any imprecise of false statement.)
>
> * RANGE OF ELEGANT TERN
>
> Elegant Tern breeds in a restricted range on the Pacific side of N
America,
> from S CA to C Baja California and from Gulf of California to Nayarit
(with
> 90% or more of the total known breeding population possibly in a single
> colony on Isla Rasa in the Gulf of California).
> It regularly wanders north to N CA as a post-breeding visitor (midsummer
> through fall). With recent El Nino events, these northern incursions seem
to
> have increased. It was first recorded in OR in 1983 but is now of annual
> occurrence. Irruption events took place in 1983 and 1990, with birds
> reaching as far north as BC - in WA, Elegant is currently described as an
> "irregular fall migrant on coast (usually absent but common during El Nino
> years)"; it is considered an exceptional visitor in Canada. I could not
find
> any record from AK.
> Elegant migrates south, to winter along the Pacific coasts of America,
> mainly in Peru and N Chile, but a few birds can remain north, as far as
> California, and others reach as far south as C Chile. I could not trace
any
> record from S Chile - all maps I have seen showed a winter range extending
S
> at most to the latitude of Santiago de Chili (i.e., still more than 2,000
km
> N of the Strait of Magellan). The species is unrecorded from Argentina.
>
> * HABITAT AND MIGRATION HABITS
>
> As far as I can see, Elegant Tern is an almost strictly coastal species.
>
> In CA, according to Joe Morlan's county lists, it is a normal visitor to
all
> coastal counties (i.e., including the counties adjacent to the San
Francisco
> Bay) but, among the 38 counties that are not directly adjacent to the sea,
> only 2 have the species on their list - Riverside and Imperial - and it is
> considered to be a rarity there. It is either unrecorded or an extreme
rare
> vagrant to any State not adjacent to the Pacific Ocean, even as close to
its
> normal range as AZ. Extralimital inland occurrences I could trace occurred
> in AZ (3 accepted records - 4 birds) and TX (1 accepted inland sight
> record) - that's all.
>
> Similarly, my impression is also that Elegant is not at all a highly
pelagic
> species. According to Del Hoyo et al. (HBW 3), "migrants feed in harbours,
> estuaries, salt-ponds and lagoons", "non-breeders feed in lagoons and bay,
> avoiding rough waters". According to all maps I have seen, Elegant's
winter
> range follows strictly the coasts. Harold Holt (A Birder's guide to
Southern
> California) lists the species as "hard to miss" along the coasts at the
> right season, but it is not even supposed to be a possibility on open
ocean
> well offshore. Silcock (http://sidney.heartland.net/silcock/) provides an
> annotated checklist of the Birds of the Pacific Region (defined as: "the
> Pacific Ocean to within 200 miles of major land masses and south to 60S",
> "northward off North America and westward south of the Aleutian Is"; check
> the site for more detail). Within this region are Guadalupe,
Revillagigedo,
> Clipperton, Coco Is. and the Galapagos (where the ornithological pressure
> can not be assumed to be low!), all of which could arguably be reached
> easily by an Elegant, providing this one showed only a slight interest in
> wandering above open waters. But, apparently, Elegant never reached ANY of
> these. In the whole region, Silcock lists only one (rather extraordinary)
> record, from Johnston Atoll (roughly 15 degrees W of Hawaii). Even if
this
> sighting seems to show that Elegant is physically able to cross oceans,
> being the only record, it also obviously shows that Elegant won't do this
> willingly.
>
> Based on this, it seems clear that either a few 10s of miles over land, or
> 200 miles over open water from an area *where Elegant is common*, are
enough
> to make it an extremely rare and accidental species.
>
> * COASTAL RECORDS ON THE ATLANTIC SIDE OF AMERICA
>
> To my knowledge, there are only two accepted records on the Atlantic side
of
> North America:
> 1) 25 Jul 1889, Corpus Christi, Nueces Co., TX: specimen, BMNH
> No.91-10-20-92.
> 2) 20 Jun 1985, Chincoteague NWR, VA: adult photographed.
>
> (Notes:
> a. There is a second record from TX:
> 23 Dec 1985, Lake Balmorhea, Reeves Co., TX: photographed, TPRF No. 397.
> But, as Balmorhea lies in the west corner of the state, close to New
Mexico
> and roughly halfway between the Gulf of Mexico and the Gulf of California,
> this record can't be assigned to the "Atlantic side of N America";
> b. Astonishingly, the VA sighting is not mentioned in Del Hoyo et al. (HBW
> 3), while the species is explicitly said to be accidental in TX.)
>
> There is/are one/two additional recent record(s) from Florida, not yet
> assessed by the Florida RC (sorry, I don't have the exact dates for the
> second record):
> 3) 3 Oct - 22 Nov 1999, Honeymoon Island State Recreation Area, FL: 1
> adult;
> 3b) Late fall - early winter 2000-01, Fort DeSoto, FL: 1 adult.
> Assuming these refer to a returning individual is obviously tempting.
>
> According to Boesman (Dutch Biding 14(5):161-169), there is also one sight
> record on the Caribbean coast of Costa Rica - but I could not find more
info
> about this bird.
> I could not trace any record from Atlantic South America.
>
> * OCCURRENCES IN EUROPE
>
> Currently accepted records of Elegant Terns from Europe are as follows:
> 1) 1974 - 1984 at least, Banc d'Arguin, Arcachon, Gironde, France: 1
> individual, not
> annually; paired with Sandwich Tern - initially ID'd as Lesser Crested
Tern;
> 2) 22 Jun - 3 Jul 1982, Greencastle Point, Carlingford, Lough, Down,
> Northern Ireland, UK, 1 individual;
> 2b) 1 Aug 1982, Ballymacoda, Co. Cork, Ireland, 1 individual, considered
the
> same as (2);
> 3) 1984, Banc d'Arguin, Arcachon, Gironde, France; second adult (!!!) in
> the
> same colony as (1), both birds paired with a Sandwich Tern; as previous
> bird, initially ID'd as LCT;
> 3b) 1985-1993 at least, Banc d'Arguin, Arcachon, Gironde, France: still
one
> individual; likely to be one of the 1984 birds, but it is unclear which
> one - caught, color-ringed and finally ID'd as Elegant in Jun 1987;
> 3c) 9, 10 & 28 Aug 1985, Sables d'Olonne, Vendee, France: 1 adult,
> considered probably one of the 2 previous birds;
> 3d) ?? Aug 1991, St-Nazaire, Loire Atlantique, France: 1 adult, definitely
> the color-ringed bird from Banc d'Arguin (3b).
> 4) 24 - 30 Apr 1993, Llobregat Delta, Barcelona, Spain: 1 adult,
> photographed.
> 5) 1995-96 at least, Ile aux Moutons, Archipel de Molene, Finistere,
> France:
> 1 individual, photographed in a Sandwich Tern colony, considered possibly
> same as (1) or (3);
>
> Currently awaiting acceptance:
> 6) 12 Jun & 15 Jul 1988, Zeebrugge, West-Vlaanderen, Belgium: 1 adult,
> photographed - originally rejected because of a possible hybrid origin but
> currently under review and could be found acceptable as Elegant (or, at
> least, not less acceptable than other European records);
> 7) 8 - 21 Jul 1999, Lady's Island, Co. Wexford, Ireland: 1 adult in
winter
> plumage;
> 8) 30 May - 11 Jun 2000, Langi, Esbjerg, Vestjylland, Denmark: 1 adult
male
> in summer plumage, displaying in a Sandwich Tern colony.
>
> There is a number of additional claims/sightings from France for which I
> don't know if they were submitted/accepted. What I traced (certainly not
> exhaustive):
> + 2 Jun 1996, Loctudy, Finistere;
> + 6 Aug - 1 Sep 1996, Sables d'Olonne, Vendee;
> + 13 May 2000, Banc d'Arguin, Arcachon.
> Situation is further complicated by an additional Elegant-like bird
trapped
> at Banc d'Arguin in 1987, for which a hybrid origin could not be discarded
> but that is considered very probably Elegant anyway. This bird was seen at
> Banc d'Arguin until 1996 at least.
>
> Rejected record:
> 1) 1 Aug 1997, Saline di Siracusa, Siracusa, Sicily, Italy: 1 adult
> (documentation and observation duration considered insufficient to allow a
> correct determination).
>
> * LIKELIHOOD OF THE EUROPEAN OCCURRENCES
>
> Absolutely NO other species with a distribution range similar to that of
> Elegant Tern has ever reached the Western Palearctic.
> It has been argued (a.o., Gutierrez, Dutch Birding 20(1):1-5) that "other
> Pacific American species have occurred in Europe as well". Of course, this
> is true. However, these species (Aleutian Tern, Parakeet Auklet, Crested
> Auklet, Ancient Murrelet, Tufted Puffin and Glaucous-winged Gull) all
breed
> much farther north than Elegant. All are extreme vagrants to the WP, with
> usually only 1 (at most 2) sightings in the last 200 years and, actually,
> there is no evidence that any of them reached Europe more than once.
> With the exception of GWGU, all are known to be highly pelagic in winter
and
> all are likely to have followed polar or near-polar routes to reach us.
> Sightings of GWGU are perhaps a bit more tricky to explain as, at first
> glance, this species is less pelagic than others, but it is nevertheless
> much more prone to cross open water than Elegant Tern (it is apparently a
> normal winter visitor to Hawaii!), it is much less likely to be stopped by
> land than Elegant Tern, it has been recorded on several occasions as far
> east as the Great Lakes and, again, the two WP records could well concern
> the same single individual.
>
> Elegant would be extremely unlikely to take a northerly route to reach
> Europe. If it does not reach Tierra Del Fuego in the south, its normal
range
> will not allow it to change of ocean without crossing land, which is
> something that this typically coastal bird will certainly not be prone to
> do. The best chance I see for an Elegant ending up on the Atlantic side
of
> America would therefore be a storm-drifted bird, pushed over land in
winter
> somewhere in Central America, which is likely what happened to the Costa
> Rican bird cited above. Note that, once it has crossed, the bird is likely
> to stay on the east side of the continent, so it's not necessary that the
> storm occurred immediately before the sighting. Anyway: this way, the bird
> would reach the Caribbean Sea. If it acts normally, it will head north in
> spring, along coasts, to appear somewhere in the Gulf of Mexico or, at
best,
> along the southern east coast. This apparently already occurred and would
> account for the TX, VA and FL reports but, in view of the extremely low
> number of sightings (one-two per century!?), it is certainly not a regular
> event. And, to reach Europe, there's still the Atlantic to cross...
>
> Also intriguing, is the fact that all European records of Elegant Tern are
> well north of Elegant's breeding range, at latitudes at which, in America,
> it is at best an uncommon post-breeding visitor, at worse a very rare
> vagrant or an unrecorded species (Northern Ireland and Denmark both lie as
> far north as southern AK). I know the climate can be different in
different
> oceans, but all other Pacific American species sighted in the WP were at
> latitudes compatible with their American range. Why would Elegant Tern be
> the exception? And what would a West Coast birder think about an Elegant
> displaying in a colony at a latitude at which Arctic Terns, Kittiwakes and
> Fulmars are all breeding?
>
> For all the above reasons, I feel that each of the European Elegant Tern
> sightings, even taken separately, would already be a totally improbable
> event - each of them perhaps even less likely than an Aleutian Tern.
> Now, what is the probability to have one Elegant breeding in a Sandwich
Tern
> colony in France for 10 years, before BEING JOINED by a second bird, and
to
> see both birds form hybrid pairs with Sandwich on that year!?
>
> Some of the European sightings are likely (and certainly, in some cases)
due
> to relocated birds, which could limit the number of individuals involved,
> but (1) in France, there were definitely 2 birds; (2) I have no data at
hand
> for Elegant but, according to Cramp et al. (BWP IV), the oldest recorded
> Sandwich Tern was 23 years old - I guess that survival in Elegant is
likely
> to be similar - European sightings cover a period that is longer than that
> and, therefore, the first bird at least is most likely dead for some years
> now; (3) is it really likely that the same bird could spend spring in
Spain
> on one year, in Denmark on another year, especially as, according to
> Gutierrez, the Sandwich Terns with which it associated in Spain were
> presumably not part of the Atlantic population, and the Spanish bird's
> description fitted better a female, while the Danish bird was a displaying
> male?
>
> In Europe, we have now reached a situation in which a "proven" pattern of
> occurrence of Elegant Tern serves as an argument to accept some birds. I
> feel this is a completely wrong way to analyse what happens. If Elegant
Tern
> reached us, it should be so rare that NO pattern should emerge. Every
> additional sighting actually increases the uncertainty, as the accidental
> character of all previous occurrences becomes less and less acceptable:
the
> existence of a pattern is, therefore, the best proof that there is a
problem
> somewhere.
>
> * SO, WHAT IS HAPPENING?
>
> Well, I don't have an all-built definite answer. I agree that (at least,
> some of the) European Elegant Terns match quite closely American birds in
> appearance.
> Obviously, we have three possibilities:
> (1) My reasoning is basically wrong. Elegant Terns do cross continents,
are
> overlooked inland, are overlooked on the east coast, do cross oceans and
can
> spend spring at the latitude of Alaska... Or, alternately, Elegant Terns
do
> reach the Strait of Magellan, are overlooked in southern Chile, are
> overlooked in Argentina and in Brazil, do cross oceans and can spend
spring
> at the latitude of Alaska...
> These are of course possibilities, but I would prefer to see evidences
that,
> at least, some of these assumptions are true. I'm ready to change my mind
> but, based on the information I have at hand, I feel this explanation is
> highly unsatisfactory.
> (2) Del Hoyo et al. (HBW 3) are correct when they state: "Odd records from
> Netherlands, Ireland, Spain and France (including hybridization with T.
> sandvicensis), but provenance of such birds in question, as species
> virtually unrecorded anywhere in North America away from Pacific coast;
> probably attributable to escapes from shipments of exotic seabirds from
> wintering grounds in W South America".
> (Note: the record from Netherlands cited here is probably an erroneous
> reference to the Belgian record, that was published in Dutch, in a Dutch
> magazine, without the word "Belgium" in the title.)
> (3) We have a big identification problem and some (all?) of the European
> sightings are NOT Elegant Terns, but something else that mimics Elegant's
> appearance - either a type hybrid or a non-described, (extremely) rare
> variation in an Old World species.
>
> These three explanations are all plausible to some extent and could even
all
> play a role simultaneously in the saga of sightings described above.
> Whatever the answer, my opinion is that the current situation is (at the
> very least) unclear and can not be explained. I feel therefore that there
is
> a real doubt about the validity of all European sightings of Elegant, and
my
> doubt will be growing with each additional accepted record. In such a
case,
> I'm afraid, the only reasonable way to treat the problem would be to
review
> and reject ALL accepted sightings and to stop accepting additional ones,
at
> least until we have a better idea about the actual origin or identity of
the
> birds involved.
> Furthermore, as the problem is global, I feel that no particular European
> record of Elegant, even extremely well documented, should be considered
> alone (except, perhaps, if the bird wears a Californian or Mexican ring).
> As long as we won't have a satisfactory global answer explaining ALL
> sightings, a doubt will remain about all of them.
>
> Reactions are welcomed (and expected ;-).
>
> * FURTHER QUESTIONS
>
> I would be interested in answers to the following questions:
> - Are there any other records of Elegant Tern on the Atlantic side of USA
> that I did not mention?
> - Are there any further records from the Caribbean Sea or any further info
> about the Costa Rican sighting? Are such Central American records
submitted
> to and assessed by any particular instance (esp., when the species is not
a
> vagrant to the coutry)?
> - I know some people on this list have experience with coastal and pelagic
> birding in Chile: do you know any record of Elegant closer to the Strait
of
> Magellan than what I stated?
> - When pelagic trips are organised off western USA (a.o., Monterey),
Elegant
> regularly stands on the lists: are these birds seen well offshore or only
> close to the continent?
> - This may be a basic question (sorry if it's the case), but has Lesser
> Crested been considered as a possibility when identifying the east-coast
> Elegant Terns?
> - I found a reference to online pics of the FL bird, but without a URL and
> I failed to find them using the classical search engines: does anybody
know?
> - Is there any known information about the temperature requirements of
> Elegant? A study linking sea water temperature off N CA, OR, WA and BC to
> the presence or absence of Elegant, during normal years, versus major El
> Nino events (1983, 1990) could perhaps enlighten us?
> - If there are any French birders out there, I would be interested to know
> in what the presumed hybrid ringed in 1987 at Banc d'Arguin differed from
> the assumed pure birds seen on the island? Is the sex of any of the birds
> known?
>
> Kind regards and good birding,
> Laurent
>
>
> Laurent Raty,
> Brussels, Belgium
[ << | >> | ^^ ]
Subject: Re: Elegant Terns in Europe??
From: Don Roberson <creagrus(AT)MONTEREYBAY.COM>
Date: 27 Feb 2001 6:44pm
I recall that in October 1991, at a meeting of representatives of various
European & American rarities committee on Texel, Netherlands, we had an entire
workshop on this topic. If my memory is correct we reviewed photos of the
claimed Elegants from France, Belgium, and Ireland at that time; Claudia Wilds
brought photos of the Virginia bird; several folks had series of Lesser
Crested; and I brought a series of Elegants from Monterey, California. We had
quite a lively discussion and Dick Forsman, as I recall, focused our attention
on various bill shape/eye placement details that might be useful in separating
Elegant from Sandwich Tern. Yes, the topic of Lesser Crested was discussed but
the real problem is separating Elegant Tern from a yellow-billed Sandwich
Tern. There is a yellow-billed race of Sandwich Tern, S. s. eurygnatha
(sometimes considered a separate species "Cayenne Tern") which nests on islets
off Venezuela to Trinidad and winters along the eastern coast of S. America
south to Argentina. I know rather little about the Cayenne Tern but there is a
color photo of a breeding colony (in Curacao) in Voous' 1983 "Birds of the
Neterlands Antilles." Vagrant Cayenne Terns need always to be considered.
In addition, there is a theory -- apparently unproven but plausible -- that a
yellow bill is the "primitive" character state of this set of terns and that
the occasional nominate Sandwich Tern can be yellow-billed. Therefore our
Texel discussion focused heavily on separating European claims of Elegant from
such yellow-billed Sandwich Terns. It is my recollection that, based on bill
shape & eye placement characters proposed by Forsman, that the group consensus
was that the photos we reviewed from France (hand-held birds which were
banded) and the photo of the bird in Belgium were that they better fit
yellow-billed Sandwich Terns than Elegants, but that the Irish bird and the
Virginia, U.S., individual were Elegants. As noted, this is simply my
recollection from some years ago now. We were hoping someone would do a more
formal review of all records and publish the research. Other Americans at the
conference included Jon Dunn, Shawneen Finnegan, and Paul Lehman; perhaps they
can confirm or dispute these recollections.
I can answer these questions directly:
1) Elegant Terns in Monterey Bay are always near-shore. The farthest
"offshore" record in Monterey County is only 10-12 miles (i.e., mid-Monterey
Bay) and that is fairly unusual. They are definately an inshore bird. They
also do not occur inland except to follow coastal rivers with tidal influcene
a maximum of 1-2 miles. However, as discussed in #3 below, their offshore
(non)distribution may be a function of the California Current more than an
antipathy to open ocean waters.
2) Elegant Terns occurr annually in good numbers in Monterey Bay in
summer/fall. Elegant Tern numbers north of Monterey Bay is decidedly tied to
warm water incursions with exceptional numbers north into Oregon and beyond
only in strong "El Nino" years (details have been published in Field
Notes/Amer. Birds/North Amer. Birds magazine over the years).
3) That being said, one cannot possibly compare distribution limits on the
Pacific Coast of North America with distributional limits in the Atlantic. The
eastern Pacific nearshore avifauna is dominated by the very cold California
Current (moving south from Alaska; with only a minor countercurrent, the
Davidson Current, along the shore in fall/early winter) while North Atlantic
distribution is dominated by the Gulf Stream and other northward-moving
currents from the tropics. Therefore lattitudinal limits in the eastern North
Pacific cannot be extrapolated to the North Atlantic.
In all, the interesting question of whether Elegant Terns reach Europe, and
how often, is less a question of weighing distributional possibilities than a
question of separating such claims from yellow-billed Sandwich Terns. As far
as I've heard, that is still very much an open question.
Don Roberson
Pacific Grove, Monterey Co., California
[I apologize for an inability to respond to any follow-up in March as I will
be on an overseas trip].
[ << | >> | ^^ ]
Subject: Re: Elegant Terns in Europe??
From: Margie Wilkinson <wcwilkin(AT)GTE.NET>
Date: 27 Feb 2001 8:01pm
In response to the query:
> - I found a reference to online pics of the FL bird, but without a URL and
> I failed to find them using the classical search engines: does anybody know?
Pictures of the FL Elegant Tern seen 12/2/00 at Fort DeSoto Park, Pinellas
County, are online at
http://home.earthlink.net/~bonniedabird/elegant_tern.htm
The tern was identified by Lyn Atherton, who determined that it was in its
first
year and thus not the same bird that spent several weeks at Honeymoon Island
SRA
in fall 1999.
Margie Wilkinson
St. Petersburg, FL
wcwilkin(AT)gte.net
[ << | >> | ^^ ]
Subject: Re: Elegant Terns in Europe??
From: Tony Leukering <GreatGrayO(AT)AOL.COM>
Date: 27 Feb 2001 9:23pm
----INCLUDING text/plain MIME SECTION----
Hi Laurent:
I am responding to one of your questions regarding Elegant Tern occurrence
patterns:
Elegant Tern is not overlooked in interior North America. Since there are no
regularly-occurring yellow-billed terns (other than Least) in that area, all
such terns receive great scrutiny and all such occurrences away from Texas
have been of Royals (e.g., a very small handful in the Great Lakes, one in
Colorado).
Tony Leukering
Brighton, CO
----DELETED text/html MIME SECTION----
[ << | >> | ^^ ]
Subject: FW: Elegant Terns in Europe??
From: Peter Adriaens <Peter.Adriaens(AT)KENDER-THIJSSEN.BE>
Date: 28 Feb 2001 7:20am
Hello Don, Laurent, and others,
I am a little confused here. All the European "Elegant Terns" have shown
bright orange bills, while "yellow-billed Sandwich Terns" are basically just
that -- Sandwich Terns with yellow bills. The subspecies eurygnatha is well
covered in the "Terns of Europe and North America" guide by Klaus Malling
Olsson and in Cramp & Simmons. It is said to usually have a pale
straw-yellow or greenish-yellow bill (which indeed seem to be the commonest
colour variant when looking at photographs), sometimes even with some black
admixed (there is some regional variation here, with up to 80% of adults in
some colonies exhibiting a large amount of black, some birds approaching or
even closely resembling the subspecies 'acuflavida'). Less than 1% is said
to have orange-red to red bills. Size and structure of 'Cayenne Tern' are
nearly identical to European Sandwich Terns; if anything, Cayenne Terns are
slightly smaller (like 'acuflavida').
Therefore, I thought that bill colour, size, and structure (notably the
longer, more drooping bill and the longer, shaggier crest) of Elegant Tern
were sufficiently distinct from all subspecies of Sandwich Tern ?
Your mail seems to suggest that the French and Belgian birds were, in fact,
yellow-billed Sandwich Terns. However, this is not at all the impression one
gets when examining the photographs; e.g. the Belgian bird was photographed
among Sandwich Terns and looks proportianately and structurally very
different, matching Elegant Tern very well.
Have the Texel conclusions been published ? Apparently they have not stopped
the French rarities committee from accepting their records.
I have no firm opinion on the origin of the European records; wether they
are genuine vagrants or escapes I do not know (and I hope to learn the
answer from the current discussion; I don't precisely recall what I said to
Laurent when he started this discussion with us last week, as we had had
some beers and the time was well past midnight...), but I find it hard to
buy the hybrid theory. I can accept that one or two hybrids may appear
identical, or rather, nearly-identical, to a third species, but a larger
sample of hybrids should reveal at least some birds with characters of one
or both parent species. E.g., thus far, all hybrids of Lesser Crested x
Sandwich Tern caught and banded in Europe have shown some black in their
bills.
Best regards,
Peter Adriaens
-----Original Message-----
From: Don Roberson [mailto:creagrus(AT)MONTEREYBAY.COM]
Sent: Wednesday, February 28, 2001 2:46 AM
To: BIRDWG01(AT)LISTSERV.ARIZONA.EDU
Subject: Re: [BIRDWG01] Elegant Terns in Europe??
I recall that in October 1991, at a meeting of representatives of various
European & American rarities committee on Texel, Netherlands, we had an
entire
workshop on this topic. If my memory is correct we reviewed photos of the
claimed Elegants from France, Belgium, and Ireland at that time; Claudia
Wilds
brought photos of the Virginia bird; several folks had series of Lesser
Crested; and I brought a series of Elegants from Monterey, California. We
had
quite a lively discussion and Dick Forsman, as I recall, focused our
attention
on various bill shape/eye placement details that might be useful in
separating
Elegant from Sandwich Tern. Yes, the topic of Lesser Crested was discussed
but
the real problem is separating Elegant Tern from a yellow-billed Sandwich
Tern. There is a yellow-billed race of Sandwich Tern, S. s. eurygnatha
(sometimes considered a separate species "Cayenne Tern") which nests on
islets
off Venezuela to Trinidad and winters along the eastern coast of S. America
south to Argentina. I know rather little about the Cayenne Tern but there is
a
color photo of a breeding colony (in Curacao) in Voous' 1983 "Birds of the
Neterlands Antilles." Vagrant Cayenne Terns need always to be considered.
In addition, there is a theory -- apparently unproven but plausible -- that
a
yellow bill is the "primitive" character state of this set of terns and that
the occasional nominate Sandwich Tern can be yellow-billed. Therefore our
Texel discussion focused heavily on separating European claims of Elegant
from
such yellow-billed Sandwich Terns. It is my recollection that, based on bill
shape & eye placement characters proposed by Forsman, that the group
consensus
was that the photos we reviewed from France (hand-held birds which were
banded) and the photo of the bird in Belgium were that they better fit
yellow-billed Sandwich Terns than Elegants, but that the Irish bird and the
Virginia, U.S., individual were Elegants. As noted, this is simply my
recollection from some years ago now. We were hoping someone would do a more
formal review of all records and publish the research. Other Americans at
the
conference included Jon Dunn, Shawneen Finnegan, and Paul Lehman; perhaps
they
can confirm or dispute these recollections.
I can answer these questions directly:
1) Elegant Terns in Monterey Bay are always near-shore. The farthest
"offshore" record in Monterey County is only 10-12 miles (i.e., mid-Monterey
Bay) and that is fairly unusual. They are definately an inshore bird. They
also do not occur inland except to follow coastal rivers with tidal
influcene
a maximum of 1-2 miles. However, as discussed in #3 below, their offshore
(non)distribution may be a function of the California Current more than an
antipathy to open ocean waters.
2) Elegant Terns occurr annually in good numbers in Monterey Bay in
summer/fall. Elegant Tern numbers north of Monterey Bay is decidedly tied to
warm water incursions with exceptional numbers north into Oregon and beyond
only in strong "El Nino" years (details have been published in Field
Notes/Amer. Birds/North Amer. Birds magazine over the years).
3) That being said, one cannot possibly compare distribution limits on the
Pacific Coast of North America with distributional limits in the Atlantic.
The
eastern Pacific nearshore avifauna is dominated by the very cold California
Current (moving south from Alaska; with only a minor countercurrent, the
Davidson Current, along the shore in fall/early winter) while North Atlantic
distribution is dominated by the Gulf Stream and other northward-moving
currents from the tropics. Therefore lattitudinal limits in the eastern
North
Pacific cannot be extrapolated to the North Atlantic.
In all, the interesting question of whether Elegant Terns reach Europe, and
how often, is less a question of weighing distributional possibilities than
a
question of separating such claims from yellow-billed Sandwich Terns. As far
as I've heard, that is still very much an open question.
Don Roberson
Pacific Grove, Monterey Co., California
[I apologize for an inability to respond to any follow-up in March as I will
be on an overseas trip].
[ << | >> | ^^ ]
Subject: Black-backed" or "Newfoundland" Robins
From: Ian Mclaren <iamclar(AT)IS.DAL.CA>
Date: 28 Feb 2001 12:09pm
All:
After e-conversations with Bruce Mactavish I'm launching
("starting" being more appropriate to hares) something new,
although it may go nowhere. There are lots of references to the
"Black-backed" or "Newfoundland" Robin, _T. migratorius
nigridius_, but the situation remains hazy at best. Probably the
last original word was in Todd's massive "Birds of the Ungava
Peninsula." Most other more recent references are based on
previous ones, although Phillips seems to have looked at some
specimens in coming to some uncharacteristically conforming
conclusions.
All sources since Aldrich and Nutt defined the subspecies
recognize that individual "black-backed" birds can occur widely,
where they might qualify either as morphs or extremes within the
normal range of _T. m. migratorius_. Todd accordingly decided to
restrict subspecies status to birds of coastal Labrador and
Newfoundland, where he thought the black-backed form "becomes
predominant in the population." He tended to dismiss this
possibility for northern areas. Without seeing specimens, he
thought that Ungava Bay birds did not qualify, although Aldrich
(accessibly quoted in Bent) had certified two males collected by
Turner in 1884 from Chimo (now Kuujuaq), at the base of Ungava
Bay. As a personal aside, I entered in my June 1951 (!) diary observations
of nesting robins at Kuujuaq that I rated as "black-backed." Others since
Todd have retained "N. Quebec" or variants of that as within the range of
_nigridius_.
One trouble is that Bruce Mactavish has seen only a small fraction of
birds, "20% at any season") that he would rate as "black-backed" in SW
Newfoundland and along the Labrador coast. And there remains the problem
of wider occurrences. Around here (NS), some black-backed males do indeed
nest (see Tufts, "Birds of NS"); I had one on my street two years
running). Although there is birder talk of "Newfoundland robins"
wintering in NS, I haven't seen black-backed birds then, although there
are fair numbers passing through in spring.
So, here are a couple of questions.
1) is there indeed any core range for "predominantly" black-
backed birds (maybe a majority of males would do?) that might
sustain continued designation of _nigridius_? Maybe it's still
possible that Ungava Bay drainage would qualify. And, maybe
our Quebec colleagues have some more recent insights on this.
2) There are lots of references to migrant or wintering specimens
deemed _nigridius_ in eastern-to-midwestern localities. Do any of
you out there have a sense of when good numbers of this
morph/subspecies appears in their area. This might give us some
clues about origins. Todd notes that the usual "birds-of-a-feather"
rule might apply to migrant _nigridius_ tending to flock together.
All this may be too arcane, particularly since no one is going to
mount a "split" on this issue.
Cheers, Ian M.
Ian A. McLaren
Biology Department phone: (902) 494-2565 (W)
Dalhousie University (902) 429-7024 (H)
Halifax, NS B3H 4J1 Fax: (902) 494-3736
[ << | >> | ^^ ]
Subject: Re: Elegant Terns in Europe??
From: Ricard Gutierrez <GUTARB(AT)terra.es>
Date: 28 Feb 2001 3:41pm
Hello:
Regarding this issue, I would like to say something as the author of one of
the mentioned papers as well as observer of the Spanish bird in 1993. Excuse
any ortographical mistakes.
First I strongly agree the commented questions regarding marine currents and
sea temperature as facts limiting bird distribution. This is a widely known
issue and e.g. in the Mediterranean, pre-breeding distribution of some
Shearwaters (Puffinus) as well as breeding terns is related to food
availability. So the latitudinal aspect has, for me, no strong value.
Second, let's remember that this is a seabird, not e.g. a parrot. These
birds are say more prepared to fly than other counterparts. And if a
passerine can cross the Atlantic, why a tern cannot?. This is only a
speculation in terms of possibilities of course.
Regarding the occurrence of the species in Europe, or of other Pacific
species in the areas mentioned it should be stressed that by all means these
situations are rare. And the number of enough skilled observers able to
identify this/these species is perhaps even rarer or scarcer. Even here in
Spain, where due to our geographical location a higher number of American
bird observations should be expected, the number is comparatively low due to
comparative lack of birders. Multiply both probabilities and you'll get an
exponentially lesser probability of detection of any vagrant out of say well
worked birding areas. These are mathematics.
Regarding the European records, all were accepted by their respective
national rarities committees which, at least in the cases I know, are not
precisely formed by people wanting to desperately add birds to the national
lists. Detailed and long discussions were held to accept the birds (at least
in the cases I know) and foreign advice was requested. As in all situations,
however, RCs are always opened to review submissions in case new evidence is
obtained.
You claimed the fact than a Pacific species has reached Europe comparatively
so many times is strange. Yes it is. But what?. The birds were (as far as we
know) Elegant terns. Another thing is where did they came from. There are
probably some records regarding to "repeated birds" but again, rarer things,
in terms of biology occur. We at the Spanish RC are currently examining an
almost incredible record of a wader species three juveniles of which not
only arrived from the Pacific but from Asia the other side of the Bering
Straits probably following the "American route" (shorter than the Asian
way). So why not a tern from a family of well-known flyers can do that way?.
Perhaps ship assistance or storms or something played a role in these
records. But despite the mentioned records, this scenario is by no means an
invasion of Elegant terns. And it is not a rare phenomenon in biology that
when a foreign species reaches the range of another similar out of their
usual ranges they tend to associate (it is the case of vagrant waders, it
was the case of these birds, associating to their commoner and similar
fellows: Sandwich Terns Sterna sandvicensis). Or in our case, in
Mediterranean Spain, the pairing Sterna sandvicensis x S.bengalensis.
Regading HBW statements on "escapes from shipments of exotic seabirds from
wintering grounds in W South America", this would be matter of
investigation. Although I honestly cannot imagine a ship filled with Elegant
Terns to be set in cages like parrots... Following a ship through the Panama
canal or a commercial route would be a different issue.
>(3) We have a big identification problem and some (all?) of the European
sightings are NOT Elegant Terns, but something else that mimics Elegant's
appearance - either a type hybrid or a non-described, (extremely) rare
variation in an Old World species.
Like Peter Adriaens I strongly disagree with this statement. What is a bird
that exactly fits all known ID characters of a species: as far as we know
simply that species (yes, except perhaps in the case of some 2nd or 3d
generation hybrids of ducks or, some gulls?). But what with our case?. At
least the bird I saw was exactly fitting the species. Can a variation change
structure of a bird?, bill length and drooping, colour of plumage, size
etc...? No: that is just another species. We have some experience here in
Spain with pairing between Sandwich (sandvicensis) and Lesser-Crested
(S.bengalensis). Results of these mixed pairs have never produced offspring
like adults (some papers published in British Birds by our RC member J.
Ignacio Díes) but a mixture of black and yellow billed birds. Structure of
Cayenne terns (S.s.eurygnatha) as far as literature says, is not different
from sandvicensis and bill colour (and size!) is very unlike elegans. If we
start thinking without further evidence that exactly fitting species are
rare hybrids of some sort (which in biological terms may be even rarer or
less viable) then perhaps let's start thinking Serins (Serinus serinus) are
in fact dwarf Greenfinches (C.chloris) of some sort [excuse me the joke
license].
And given the current functioning of European RCs (see the web page of
AERC), our committees do accept bird identification then most of us also
assigning a possible origin giving a letter (ABCDE) regarding its status.
Even in the case these birds would be proven as escaped, they will never be
rejected but changed of category from say A to E or D in case of reasonable
doubt.
My final thought is that when dealing with animals, and now I talk as a
wetland manager, you cannot always expect satisfactory global answers
explaining everything just because sometimes animals behave like that
without an expected pattern or reasons. Caution is needed but my personal
feel is that I don't see anything extremely strange or doubtful in this
case.
Ricard Gutiérrez
CR/SEO
Spain
http://www.terra.es/personal3/gutarb
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