Dead bird quiz answers

25 09 2009

 

Bird A was a greater shearwater. Not that you Seanetters even hazarded a guess. Sigh.

Bird A was a greater shearwater. Not that you Seanetters even hazarded a guess. Sigh.

Oh come on! Not a single guess on yesterday’s dead bird quiz? I’m shocked, SHOCKED, Seanetters. I suppose I must reveal the answers nonetheless. Bird A is a Greater Shearwater. These guys are often misidentified by even relatively experienced birders since they so rarely appear near shore, and essentially only come on land to breed. Or to die, in this case. They are sometimes reported as cormorants, owing to that long, hooked bill. But closer inspection should reveal the characteristic tubenose sported by shearwaters and albatross. This particular specimen was rather bedraggled, so measurements are crucial to confirming the i.d. True dead bird nerds will consult their trusty beached bird field guide and see that the measurements provided in the photo of Bird A are spot on for a greater shearwater.

Bird B is definitely a cormorant. But what sort? The ubiquitous Double-crested Cormorant is a common finding on many SEANET beaches up and down the coast. But Bird B is, remarkably, not a Double-crested. Bird B is the first confirmed Great Cormorant found by a Seanetter in the past three years! Given their rarity, a cautious Seanetter could be forgiven for assuming that all dead cormorants are of the Double-crested variety, so here are a few tips for discerning the difference.

First, the Great Cormorant is substantially larger than the D.C. This, however, can be difficult to appreciate unless the two obligingly drop dead side by side on your beach. Alternatively, you can examine the head of your mystery cormorant.

Bird B was a Great Cormorant, much like this one, but more dead.

Bird B was a Great Cormorant, much like this one, but more dead.

The Great Cormorant has a relatively small patch of yellow or orange skin at the base of the bill, and a variably sized white patch on the throat just behind that. The white is much more extensive in adults than in our Bird B, a juvenile. The Double-crested Cormorant, on the other hand, has no white feathers on the throat at all, and much more extensive yellow or orange coloring.

Finally, the white belly on our Bird B is unique to juvenile Great Cormorants. They grow out of it by adulthood, and Double-crested lack any white on the belly at any age. 

Double-crested Cormorant; cousin to our Bird B

Double-crested Cormorant; cousin to our Bird B

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One response

28 09 2009
birdingperu

It is hard enough as it is with live birds. But great walk-through for the ID. Just discovered your blog. Keep up the good work.
Saludos

Gunnar

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