Thanks, Peter, for sharing this. Although the original hard copy of the article is right here on my shelf, I remembered it only dimly until you posted the link.
Among the many characters discussed by the authors are two that I'd like to follow up on now, while everything is fresh in our minds. The first involves the pattern of the secondary coverts, which in Brewer's Sparrow are described as showing pointed black extensions along the shafts, described as absent in Clay-colored Sparrow. I had noticed that the Queens bird showed such points, and worried about this a little bit until I confirmed that multiple of my images of Long Island Clay-colored Sparrows also clearly show this pattern: https://picasaweb.google.com/109808209543611018404/Spizella# I don't have an explanation for this discrepancy, but it underscores the need to look at multiple characters when trying to distinguish very similar species. The second involves the relative tail length character mentioned in a number of posts. Whereas the article does not mention this as a useful field character for distinguishing Brewer's and Clay-colored, it is well known that these two species collectively differ from Chipping in being longer-tailed, relative to body size. This may not be immediately obvious from the table of measurements, because the tail length values for Chipping Sparrow are basically identical to those for Brewer's and Clay-colored. But the key point is that Chipping Sparrow is larger than the other two, as seen most obviously in its much greater wing length values. Thus, what might appear to be an obscure bander's formula, "wing minus tail" is in fact an elegant way of expressing relative tail length, and it is evident from the table that Brewer's and Clay-colored are similarly long-tailed compared to Chipping. Using wing length as a proxy for body size is appealing because these data are relatively accessible, but the validity of this approach is restricted to closely related species that have similar wing shapes. In the case of the Spizella sparrows, I think this is generally true. If anything, I think Chipping might be a little be longer-winged (relative to body size) than the other two, with a slightly longer primary projection, but I still think Clay-colored looks consistently longer-tailed than Chipping in the field and suspect that Brewer's does also. Shai Mitra Bay Shore ________________________________________ From: [email protected] [[email protected]] on behalf of Peter Reisfeld [[email protected]] Sent: Wednesday, December 23, 2015 12:59 AM To: [email protected] Subject: [nysbirds-l] Spizella sparrows For those wishing to delve a bit more into this topic, here is an old review discussing the range of variation of features within species, and clues to help separate them. http://www.birdpop.org/docs/pubs/Pyle_and_Howell_1996_Spizella_Sparrows_Intraspecific_Variation_and_ID.pdf Happy winter birding, Peter -- NYSbirds-L List Info: Welcome and Basics<http://www.northeastbirding.com/NYSbirdsWELCOME> Rules and Information<http://www.northeastbirding.com/NYSbirdsRULES> Subscribe, Configuration and Leave<http://www.northeastbirding.com/NYSbirdsSubscribeConfigurationLeave.htm> Archives: The Mail Archive<http://www.mail-archive.com/[email protected]/maillist.html> Surfbirds<http://www.surfbirds.com/birdingmail/Group/NYSBirds-L> BirdingOnThe.Net<http://birdingonthe.net/mailinglists/NYSB.html> Please submit your observations to eBird<http://ebird.org/content/ebird/>! -- ________________________________ Support CSI students this holiday season each time you shop with Amazon Smile<https://smile.amazon.com/ch/13-3683723> -- NYSbirds-L List Info: http://www.NortheastBirding.com/NYSbirdsWELCOME http://www.NortheastBirding.com/NYSbirdsRULES http://www.NortheastBirding.com/NYSbirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/[email protected]/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/NYSBirds-L 3) http://birdingonthe.net/mailinglists/NYSB.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
