Mystery Bird #4 - The Answer

Monthly challenge to test and improve your bird identification skills.
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Mystery Bird #4 - The Answer

Postby sav » Mon Oct 18, 2010 4:36 pm

Hi everyone,

Well, that was a bit harder than I thought it might be! Terns can be tricky at the best of times and this one managed to fool more than half of the entrants.....

It is fairly obviously a Sterna tern with very pale plumage, a long black bill and thick red legs. Arctic, Common and White-fronted are the main contenders. The only reference one should need is Heather and Robertson, and Derek Onley's excellent illustrations.

It isn't an Arctic. The bill is way too long and Arctics have very, very short legs - not "sort of short" like this. Also an Arctic in this kind of plumage should have white extending way past the eye and right onto the top of the crown. And the wings are very pale.....

It isn't a Common. The bill is again too long, and the legs too thick. Common Tern has rather spindly legs, unlike these whoppers. And the wings are too pale. Note that there is virtually no contrast between the ground colour of the tertials and the tips, Common Tern always shows a distinct white band of tertial tips because the basic feather colour is a couple of shades deeper than what we have here. The primaries should also be much darker.

The bird is a non-breeding adult White-fronted Tern. First impressions are important as always - it just looks like a big, pale tern!! I imagine that one fact that threw many of you was the colour of the legs. But White-fronts CAN, and do, have red legs at times - honest! Take a look at any decent sized flock and surprise yourself.

Thanks to all those that entered. Remember that evrey entry, right or wrong, will go into a draw for the binoculars. Tony Wilson is the only one that has the first 4 all correct, but there are 5 entrants with 3 right. More next month......

Sav Saville
Wrybill Birding Tours, NZ
Great Birds, Real Birders
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Shane McPherson
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Re: Mystery Bird #4 - The Answer

Postby Shane McPherson » Tue Oct 19, 2010 4:57 pm

yep, those red legs threw me! Thought maybe the ankle was visible because it was standing tall (like how I tripped up on the sand plover Q)

c'mon with another acoustic test ;)

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