Proposal (25) to South American Classification Committee
Add Morus
capensis (Cape Gannet) to main list
Manuel
Plenge pointed out to me the recent publication of a photograph of Sula/Morus
capensis in the paper that I circulated to all of you as a pdf file:
García-Godos,
I. 2002. First record of the Cape Gannet Morus capensis for Peru
and the Pacific Ocean. Marine Ornithology 30: 50.
We have
this species on the Hypothetical List based on sight records from Brazil and
Argentina (the latter possibly also a photo -- Alvaro is checking).
What I
know about gannet identification was learned only moments ago. I think I see
enough in the head and throat in the photo to exclude the similarly plumaged
adult Masked Booby (Sula dactylatra), and the brief description notes
presence of long gular patch and yellow wash on head. The black secondaries and
rectrices, clearly visible in photo, eliminate N. Gannet (Morus bassanus).
The key characters for distinguishing M. capensis from M. serrator
are reduced black in rectrices and shorter gular stripe in latter. I cannot
discern the length of the gular stripe from the photo. However, it is clear
that the outer rectrices are black; if this is indeed diagnostic for capensis,
as is widely reported in standard literature, then it "has to be" capensis.
If anyone has information to the contrary, please speak up. With the caveat
that I do not know these birds in detail, it seems safe to conclude that by
conventional standards the photo does document the species for South America
(and first for Pacific Ocean).
Van Remsen, 3 March 2003
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Comments from Jaramillo: "I
looked into it a bit, and indeed it’s a match for capensis. I also sent
it to Ned Brinkley who has a great deal of experience with Gannets, including
oddly plumaged adults observed in North America which have shown features
suggesting other gannet species. He felt that the photo was of a classic capensis,
with the gular stripe being a clincher. I vote YES to accept this species to
the main list. I also apologize that I have yet to lay my hands on the photo
that I recall of the Argentine record which was in El Hornero, a journal that
is not all that easy to get around here. Even more difficult to get when the
year one is looking for is out being bound!
Comments
from Schulenberg:
"I don't know a lot about Sula capensis, but based on what I do
know, this photograph seems to be identified correctly. I assume that Sula
serrator always has white outer rectrices, otherwise the identification
would become more problematic. So I vote "yes". I seem to recall, a
number of years ago, a report in British Birds on the first occurrence in the
United Kingdom (and in all of the Western Palearctic?) of a vagrant from North
America. The bird was photographed, and there was no question of the
identification (Bay-breasted Warbler, if I remember correctly, which I may
not). However, there was only a single observer of this bird. So the British
records committee went to some trouble to have the plants that were visible in
the photograph identified to species, in order to confirm that the photographs
indeed were taken on the correct (eastern) shore of the Atlantic Ocean. At the
time I thought, "Oh, those Brits. What a silly people, never missing an
opportunity to be pedantic little poops". But now, even though I am voting
to accept the record, I admit that I'd feel better about my actions if there
were something visible in the photograph that would help confirm that the
photograph came from Peru."