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Tanzania - Black Tern? (1 Viewer)

Garrett Lau

Well-known member
I photographed this tern at Lake Manyara in Tanzania on June 24. I am thinking that the extent of the black makes it look more like a Black Tern than a White-winged Tern, but Black Tern would be quite rare there. I would appreciate any analysis.
 

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I can't see any reason why it wouldn't be an over-summering White-winged Tern, especially based on just this one photo.
 
The more I look at this bird the more it looks like a 2cy Whiskered Tern to me. Although quite small-billed for Whiskered, it looks fairly deep-based and has a fairly well-developed gonys angle. Furthermore, the head pattern just doesn't fit what I'd expect for typical WWBT, which has lots of clean white on the forehead and behind the 'earphones'.

This bird has too much crown streaking, which extends well down onto the forehead and loral area, leaving just a white supercilium and eye-crescent which is enclosed by subtle grey tones/streaking. Same thing behind the earphones, with subtle streaking linking the solidly dark ear coverts to the well-streaked rear crown and nape.

WWBT should show a much crisper definition between black and white areas, and an even smaller bill.

If you need convincing further, and you have the Lewington/Howell/Russell guide to Rare Birds of North America, compare head patterns on pages 139 and 141. It's a dead-ringer for the young Whiskered upper-left on p141.
 
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Thanks for the detailed analysis. That's very interesting. FWIW, the only other terns that I could identify in the park that day were Whiskered Terns.
 
And WWBT does not breed in East Africa...unlike Whiskered, hence a fresh 1st cycle bird in June can only be a Whiskered over there.
 
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