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ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia

Unknown Tern (Netherlands Waddenzee August 20th 2018) (1 Viewer)

Frank-birding

Frank van de Velde
Supporter
Could anybody help me to identify a Tern I have trouble to recognise? Photos taken from very far off, on a windy overcast day. (Sorry for the lack of clarity.) Netherlands, August 20 2018, Island of Terschelling, Waddenzee side.

The Tern has short red legs (visible in some of the images) and perhaps a slight red base to its bill. Its size is quite small, compared to Common Gulls in the background and Black-headed Gull left.
Confusing me is the light tip of the bill. Its small size and red legs seem to rule out Sandwich though.
Common is very likely of course, but do light tipped bill and strange (very long, unequally extending) shape of its primaries (way longer than tail it seems) fit Common? I'm equally hesitant about Artic (short apparent tail fits Artic even less).

Regards, Frank
 

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SteveClifton

Well-known member
I think on general structure (esp bill and leg length) this has to be a Common Tern.
It could be an adult transitioning into non-breeding plumage, or possibly a 2nd or 3rd calendar year (quite a few 2cy have dark bills).

Not sure why the bill tip would be pale but it's the only odd thing about this bird. I wouldn't worry too much about that as everything else is within variation of Common Tern IMO.
 

CARERY

Well-known member
I think on general structure (esp bill and leg length) this has to be a Common Tern.
It could be an adult transitioning into non-breeding plumage, or possibly a 2nd or 3rd calendar year (quite a few 2cy have dark bills).

Not sure why the bill tip would be pale but it's the only odd thing about this bird. I wouldn't worry too much about that as everything else is within variation of Common Tern IMO.

Agreed.
 

Frank-birding

Frank van de Velde
Supporter
Thank you Steve and Roland,

I'll book the Tern as a Common then in all peace of mind.
Also Steve's explanation is much appreciated, as it provides an opportunity to learn something more about ID-ing Terns.

Regards, Frank
 

Deb Burhinus

Used to be well known! 😎
Europe
Not sure why the bill tip would be pale but it's the only odd thing about this bird. I wouldn't worry too much about that as everything else is within variation of Common Tern IMO.

I agree with Common Tern - interestingly, this point about a pale bill tip came up on another thread while back causing confusion of a Sandwich with Common. Common Terns apparently can and do show a pale bill tip at times but it’s only ever diffuse and small never as distinct as the pale tip in Sandwich Tern.

https://macaulaylibrary.org/asset/255975281
https://macaulaylibrary.org/asset/263169621
ST
https://macaulaylibrary.org/asset/255975731
 

pianoman

duck and diver, bobolink and weaver
Always assumed Common terns with light foreheads were juveniles - can adults be seen in Northern Europe in winter plumage? For my own education...
 

Nutcracker

Stop Brexit!
Always assumed Common terns with light foreheads were juveniles - can adults be seen in Northern Europe in winter plumage? For my own education...
Juvs, and 1st-summers (a year old), maybe 2nd-summers too, can show light foreheads. Whether full adults ever show it before migrating south, not sure.
 

CARERY

Well-known member
1st summer (2cy) birds are not too rare in Europe... they show the white forehead. I'm not sure about winter plumage adults here...

edit: I took my time to post ;), nutty was faster
 

SteveClifton

Well-known member
Some pics from a mixed flock of 300+ terns from earlier this week in NE England. Majority were Common Terns but a few Roseates present too (11) and a handful of Arctics.

At least half of the Common Terns were already well on the way to winter plumage, with variable white foreheads and darker carpal bars - some still with begging young present (lower left). A few also had darker bills (upper left), while some were still clearly in full summer plumage (upper extreme right).

Same story with the Roseates, with white foreheads and dark carpals beginning to come through on some (ad and juv lower right).
 

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pianoman

duck and diver, bobolink and weaver
Thanks Steve - a bewildering array! Does the ringed bird in bottom right pic have a rosy flush or is that my imagination
 
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
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