Monday, July 20, 2009

Quiz #309 (2009-3-04) Answer

Click the picture for a larger view.

Answer by Tony Leukering

Though I received responses involving nearly as many incorrect species as correct answers, the plurality of respondents got this week's quiz correct. Nearly all answers involved some species of Tringa sandpiper, which is the correct genus, but 11 of those 21 didn't select the right Tringa.

Starting at that genus, the fact that the bird is in alternate plumage tells us that the picture was taken in spring or early summer, as all Tringas are fairly early breeders (for shorebirds), seeing as how none of them are truly arctic in nature. The thickness of the bill base rules out the stiletto-armed Solitary, Wood, Green, and Marsh sandpipers, and Lesser Yellowlegs, with the strong and wide blackish bars on the scapulars and tertials assisting in eliminating some of those species. The white side to the rump and the vaguely gray tail without any pattern is fine for Greater Yellowlegs and Willet, but the tail pattern (or lack thereof) is wrong for Spotted and Common sandpipers. Additionally, those species are also ruled out by our bird's strong dark chevrons on the sides and flanks. Obviously, the complete lack of solid black plumage rules out Spotted Redshank. Common Redshank has legs too bright orange (what we can see of our bird's legs look dull yellow) and they have bright orange bill bases. Finally, Greater Yellowlegs has tertials that are blackish with white spots or bars, not our bird's brownish tertials with strong black bars.

I took this picture of an adult Willet at Nummy Island, Cape May Co., NJ, on 30 May 2009. The data on date and location should let us know that our quiz bird is of the eastern form, but we can also tell that from the extensive dark patterning of the upperparts, particularly its well-marked head and neck.

Incorrect species provided as answers:
Lesser Yellowlegs - 2
Limpkin - 1
Solitary Sandpiper - 2
Greater Yellowlegs - 7
Blue-winged Teal - 1
Red-throated Loon - 1
Short-billed Dowitcher - 1
White-rumped Sandpiper - 1

The 10 of 26 providing the correct answer:
Tyler Bell
George Cresswell
Andy Dettling
Peter Wilkinson
Al Guarente
Mark Dettling
Aaron Brees
Su Snyder
Robert McNab
Chishun Kwong

Answer: Willet