Monday, August 20, 2012

Quiz #463 (2012-3-08) Solution

Click on picture(s) for a larger view.

Solution by Tony Leukering

Ah, a nice, bright, red bird, well-lit and in focus. While we could certainly wish that that bird's head would be turned just a bit more our way, there really is no doubt that this is a male Northern Cardinal. End of story. For that bird, at least. There is a second bird in the picture that requires a bit more work and care. Much of that bird is hidden behind the male Northern Cardinal -- and the red bird looks roughly similar in size, perhaps a bit smaller, but we can see that the entire upperparts are a medium gray, that the tertials have white tips or fringes, and that the tail is long and blackish. Unfortunately, most of our ABA-area options with such upperparts and tertials sport white on the tail, which just does not appear in our quiz picture. Well, this iteration of the CFO Photo Quiz is all about structure and posture. So, let's get on with it.

Species that we might consider include both gray shrikes (although, why is the Northern Cardinal right next to something that would be more than happy to eat it?!), Townsend's Solitaire, Northern Mockingbird, Phainopepla, and Pine Grosbeak. First, recall the placement of the individual tail feathers when the tail is folded. From the topside on a completely folded tail, we can see only the two central rectrices (r1 on each side), while from underneath, most of what we can see is the pair of outermost rectrices (r6 on each side). So, since we're looking at the bird from above, as it were, even if it had extensive white on the outer rectrices, we would probably not see it on this tightly folded tail. So, that tail neither rules out the array of species with white on the tail, nor rules in Phainopepla or Pine Grosbeak.

We are not left with much to go on, but the primary reason for using this picture is all about leg length. You see, of the six options, only one of them has long legs, Northern Mockingbird. In the below image cut out from the quiz photo, I have arrows pointing to various legs in the picture (NOCA=Northern Cardinal, NOMO=Northern Mockingbird); note that the gray bird's left leg is mostly hidden behind the red bird's right leg.

In such a picture of any of the other candidate species, we would see nowhere near as much leg and, in fact, Townsend's Solitaires often show almost no leg at all, their legs are so short. Finally, I have inserted, below, another picture taken of this duo just seconds later; the image is not much different, but does provide more evidence for an ID of Northern Mockingbird that was present along the shores of Lily Lake, Cape May Point, Cape May Co., NJ, on 16 April 2012.

Note: I could swear that when I first looked at responses early last week that one respondent had noted leg length as a major ID point, and I was going to congratulate that person. However, I cannot find such now. Ah, well, it's heck getting old!

Three respondents provided answers with only one species, all Northern Cardinal.

Incorrect species provided as answers:
Plumbeous Vireo - 1
Townsend's Solitaire - 1

Congratulations to the 17 of 22 respondents getting the quiz correct:
Tyler Bell
Jeff Witters
Robert McNab
Ben Coulter
Christian Nunes
Nick Komar
Richard Jeffers
Margie Joy
Logan Kahle
Al Guarente
Margaret Smith
Su Snyder
Peter Wilkinson
Bryan Guarente
Kirk Huffstater
Joe Bens
Sean Walters

Answer: Northern Mockingbird, Northern Cardinal