Saturday, January 3, 2009

Quiz #280 (2009-1-01) Answer

Click the picture for a larger view.

Answer by Tony Leukering

I started the year off with a bit of a stumper, with 20 respondents providing answers including no incorrect species, but not providing enough correct species. Quite a few first-time respondents jumped into the game, with, unfortunately, not all of those having read the quiz rules. At least two of the newbies provided answers with only one species listed.

The primary beastie in the picture is the loon on the left side, with all but two respondents getting that species correct. Yes, the bird does sport a white flank patch, but that, alone, does not an Arctic Loon make. That the bird's eye is in the white of the face and that the bill is very short and thin tells us that the loon is a Red-throated.

Now, for the two black birds in the background right that look of fairly similar size to each other. Few respondents provided rationales for their answers, but of those that did, most mentioned the white on the head of at least the left of the two black birds. That, obviously, would rule out Black Oystercatcher. Yes, both birds have orange bills but, to me, they don't look nearly long enough to be those of oystercatchers. So, with both birds having obvious necks (something that alcids tend to lack), the only other option for the left black bird would then be an adult male Surf Scoter, as the white appears to be on (at least) the crown. On this bird, note that the bird's head is fairly substantial and that it is attached to the body with a thickness of neck that looks proportionately appropriate.

With that bird IDed, let's take a closer gander at the right black bird. Most respondents assumed that the two black birds were of the same species, but the right bird seems to have a thinner neck and a smaller and rounder head that gives the bird the impression of the head and neck being something of an afterthought and just stuck onto the body with some Elmer's glue or something. Perhaps the sexes of Surf Scoter have differing structures in this regard. Unfortunately, we can see that the right bird has orange on the bill, a black belly, and appears to lack any pale in the head plumage, features at odds with both immature males and all ages of female Surf Scoters. If the two were flying more parallel to our view (rather than going away to the left), the right bird would probably show a longer tail than that of the Surf Scoter, but that's obviously not really noticeable at this angle.

I took this picture of a juvenile Red-throated Loon and adult males of both Surf and Black scoters off the beach in the vicinity of Beach Haven, NJ, on 31 October 2008. I want to say a particular "well done!" to those getting this week's quiz correct, as there aren't many with the eye and experience to correctly ID both scoters with the poor view provided.

Tallies of incorrect answers for quiz species:
Arctic Loon - 1
Black Oystercatcher - 4
Common Loon - 1
American Coot - 1

The 9 of 34 providing the correct answer:
Robert McNab
Andy Dettling
John Bissell
Brandon Percival
Tyler Bell
Bryan Guarente
Peter Wilkinson
Thomas Hall
Andrea Smith-Guarente

Answer: Red-throated Loon, Surf Scoter, Black Scoter