Quiz #427 (2011-4-09) Solution

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Solution by Margie Joy and Tony Leukering

Margie Joy submitted a detailed answer that covers most of the bases, so we'll start with that.

"This week's quiz bird is a diving bird: grebe, loon, or duck. Since I can only see the bird's back and sides, I'm using the pattern on the back (very dark with crisp, randomly-arranged white speckles) to collect possibilities for the ID. Some grebes and diving ducks show an indistinct scaly pattern, but it's usually gray on gray, never the sparkly effect shown in the photo; I'm going right to loons.

"Several ABA-area loons show similar patterns to that of the quiz bird. Common and Yellow-billed loons in breeding plumage show bold black-and-white spots that are arranged in a tight checkered pattern. Non-breeders and juveniles of these two species show more indistinct patterns. Arctic and Pacific loons in breeding plumage show larger white patches in a barred pattern. Non-breeders of these two species show very indistinct patterns, while juveniles show small pale areas arranged in a distinctive scalloped pattern. That leaves Red-throated Loon. Non-breeding adults have the same sparkly pattern of white on dark gray or black that's shown on the quiz bird, so I'm guessing that this bird is a Red-throated Loon. To confirm my guess, I have found other marks that are good for Red-throated: white sides and speckled rump."

Thanks, Margie. To round out this solution, I have some disparate comments. All loons have black primaries and all have long wings such that they sport fairly extensive primary projection. Unfortunately, The Sibley Guide illustrates Red-throated with the wingtips obvious, but with those of the other loons not. Juveniles of all loons other than Red-throated have pale fringes to the scapulars and coverts forming a scalloped pattern to the upperparts on swimming birds. Red-throated Loon shows such in no plumage, with the pale marks on these feathers being restricted to well-defined spots or short bars on the interior of the feathers, not on the edge. Thus, the species, as Margie described it, looks sparkly. Like stars, which may be the cause of the species' specific epithet being stellata (meaning "starry").

Peter Wilkinson noted that he "hadn't realised how hard it can be to
distinguish from juv Northern Gannet." Indeed, the patterns on the scaps and coverts are remarkably similar. However, a Northern Gannet with that pattern on the wings would not have bright white sides. Finally, as noted by multiple respondents, the bird's legs are set well back on the body, unlike that for Northern Gannet.

I took this picture of a diving adult Red-throated Loon in basic plumage at the Cape May ferry terminal jetty, Cape May Co., NJ, on 18 February 2011.

Incorrect species provided as answers:
Common Loon - 1
Arctic Loon - 2

Congratulations to the 14 of 21 getting the quiz correct:
Robert McNab
Tyler Bell
Jeff Jones
Nick Komar
Pam Myers
Christian Nunes
Kirk Huffstater
Thomas Hall
Bryan Guarente
Josh Parks
Patty McKelvey
Margie Joy
Al Guarente
Liston Rice
Marcel Such
Joel Such
Margaret Smith
Sean Walters
Peter Wilkinson
Devich Farbotnik

Answer: Red-throated Loon

Quiz #426 (2011-4-08) Solution

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Solution by Tony Leukering

As noted by Robert McNab, using only a single field mark, this bird would be impossible to separate from Nutting's Flycatcher! Yes, the quiz bird and Nutting's Flycatcher share the character of orange mouth linings, but I don't think that anyone actually thought that this bird could be a flycatcher!

We don't have a lot to go on to winnow the possibilities, but the generally white coloration with, apparently, gray wings, webbed feet, and dark eyes and legs might plop us into the Laridae, home of the gulls and terns. Dark legs are not common in gulls, but relatively so in terns, so let's start there. With the foreshortening of the bill due to the picture angle, determining bill length is problematic. However, bill color is accurately gauged: yellow with a dark tip. That greatly whittles the possibilities among the tern species recorded within the ABA area, as only Least Tern sports such a bill pattern, though Large-billed might at times. However, neither of those species sports black legs, so into the gulls we go.

ABA-area dark-legged gull species include Ivory, Franklin's, Laughing, and Heermann's gulls and, of course, Black-legged Kittiwake. The gray wings of our quiz bird rule out Ivory Gull and the white body does the same for Heermann's Gull. The paleness of the wings and the bill color rule out Franklin's and Laughing gulls. However, it should be noted that even ignoring the black legs, the unmarked white underparts on an immature gull (note the black on the tail) actually rule out nearly all options. Steve Mlodinow took this picture of a 1st-cycle Black-legged Kittiwake -- one of an amazing two present -- at Windsor Lake, Windsor, Weld Co., CO, on 5 May 2011. One of the birds had been present since early April!

Incorrect species provided as answers:
Ring-billed Gull - 2
Mew Gull - 1

Congratulations to the 18 of 21 getting the quiz correct:
Thomas Hall
Pam Myers
George Cresswell
Peter Wilkinson
Patty McKelvey
Robert McNab
Jennier Courtemanche
Christian Nunes
Ira Sanders
Tammy Sanders
Josh Parks
Margie Joy
Su Snyder
Devich Farbotnik
Nick Komar
Al Guarente
Kirk Huffstater
Bryan Guarente

Answer: Black-legged Kittiwake