Dead Bird Quiz answers

22 02 2011

Mary Wright and John Stanton can always be relied upon to answer, and on this quiz, I even got my good friend Sarah Kern to take a look and offer her guesses. The Dead Bird Quiz is clearly catching on!

So, here are the answers insofar as I have any:

Razorbill tail projects beyond the feet.

Murre tails are quite stubby and end well short of the feet

Bird A: John and Mary are both right, in my opinion. It’s definitely an alcid (black and white bird with white-tipped secondary feathers; small, webbed feet) and the wing chord of 22cm makes it much too big to be the diminutive Dovekie. John answered that it’s either a Common Murre or a Thick-billed Murre. Mary wrote that the wing chord is too long to be a Common Murre, so it must be a Thick-billed. True indeed, the wing chord range for a Common Murre is 19-21cm, while the range for the Thick-billed is 20-22cm. The only trick here comes with the variability we find in our volunteers’ wing chord measurements. Published data on wing chords tends to be more constrained in their ranges because the data are generated by fewer observers with extensive experience. Our volunteers typically show more variation in their measurements, so while Thick-billed is by far the most likely i.d. (an inch is a lot when it comes to wing chords, after all), we cannot entirely rule out the possibility that it’s a Common Murre. Finally, why not a Razorbill? The measurements match, and without the head, how can one tell? Mary solved this mystery as well, pointing out that Razorbills have longer tails. In fact, Razorbill tails extend past the feet, while murre tails don’t even come close.

Bird B, as both Mary and John assert, is a female Common Goldeneye. The golden colored iris that gives the bird its name is, sadly, not often evident in dead specimens. But in a whole carcass, there are plenty of other markings that identify this species. For females, these include a reddish-brown head,  a dark bill that develops a small amount of  yellow at the tip in adulthood, a gray back and breast with a white belly.

Female Common Goldeneye: this photo shows the extensive white speculum on the wing.

Finally, Bird C. This one, not surprisingly, has caused the most trouble. It was not very fair of me to withhold the wing chord on this one, which was 24cm. Even with the caveat given above regarding wing chords, that is well outside the range of the little Bufflehead (wing chord: 14-18cm). So, given that relatively large size, another possibility is Mary’s answer, Long-tailed Duck. Mary also hedged with the comment: “maybe those white feathers aren’t scapulars, but the inner part of the wings . . . We await the official word from Sarah . . .” While I cannot profess to have the official word, being only a self-taught dead bird afficionado, I contend that this is another Goldeneye. Just as Mary said, the white feathers on Bird C are not scapulars, but are part of the wing proper; Bird C has a white speculum that extends almost to the leading edge of the upper wing. From the wings only, I don’t think it’s possible (at least for me) to determine whether this is a Common Goldeneye or a Barrow’s Goldeneye, though the Barrow’s is a much more northern species and Cape Cod (where Bird C was found) is the southern limit of the Barrow’s typical range, so odds are that Bird C is a Common.

Bufflehead (male) upperwing: similar to Goldeneye except MUCH smaller.

Long-tailed Duck in flight: the wing proper is all dark. White feathers are limited to the back and scapular region.

Common Goldeneye (male) upperwing.

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