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Re: Caspian vs. Royal Tern



In addition to the color difference, Caspians are almost always noticeably
bigger than Royals when viewed side-by-side.  They also usually (in mature
birds) have some darkening at the bill tip.  The crest on Royals is slightly
more prominent, too, I believe.  If the birds was definitely the same size
as the Royals, I'd suspect it to have been the same.

-Sandy

-- 
Sandy Cash
Durham, NC

"The time for change is here and here we are, we're just for you!" -
Funkadelic
----- Original Message ----- 
From: "Shantanu Phukan" <phukan@email.unc.edu>
To: "Carolina Birds" <carolinabirds@duke.edu>
Sent: Friday, April 25, 2003 5:31 PM
Subject: Caspian vs. Royal Tern


> This is a question I have been meaning to ask on this list for more than a
> week now. Last week I wnet down to Fort Fisher and came upon a mixed flock
> of Terns on the spit. THere were Royals, Sandwiches and Forster's all
> resting and preening together. In this flock was one tern that looked very
> much like a Royal but had a definitely red (and not orangish) bill. It
> held itself just a little apart from the other Royals. Now I know that
> Caspians have a reddish rather than orangish bill and on this point this
> tern would have been a Caspian. However, its bill was not any the thicker
> than that of the dozen or so Royals sitting next to it. Nor was the tern
> itself any larger than the Royals. None of the other Royal terns showed
> any variation in the bill color--they all had the orangish bill that they
> are supposed to have according to the guide books.
>
> So, my question is is there much bill color variation in Royal terns, with
> some of them inclined towards red rather than orange. Or is the red such a
> definite diagnosic mark that its presence (despite no size difference)
> would clinch this as a Caspian.
>
>
> THe second question is regardng Sandwich vs. Gull Billed Tern. Yes, I know
> that Gull Billed Terns have a shorter and thicker bill; however, when one
> sees a lone tern with nothing to compare it to it is difficult to decide
> if the bill is thick enough or not and I have now several times decided
> that a tern was Gull billed only to then finally see the little yellow tip
> as it turns and catches the light. So is there any other clue besides the
> lenght and thicknessof the bill. If, for example, one sees a Gull
> Billed/Sandwich Tern over the ocean can one definitly rule out the GUll
> Billed since they are supposed to feed on mudflats and grassy fields?
>
> Any thoughts woudl be greatly appreciated.
>
> Shantanu Phukan
>
> *****************************************************
> SHANTANU PHUKAN
> Lecturer in Urdu-Hindi & Indian Literature
> University of N. Carolina, Chapel Hill
> Curriculum in Asian Studies
> Alumni Hall 413C
> Chapel Hill, N.C. 27599
>
> phukan@email.unc.edu
> 919-962-6825
> *****************************************************
>