For the issue of the covert patterning figure 19E and the legend for that figure suggests an explanation. As for tail length the pictures of the Queens bird that I saw did not show a fully grown shape and it seems very likely that it is still growing, making conjecture about relative or absolute tail length rather hazardous.
Cheers Phil Jeffrey Princeton > On Dec 24, 2015, at 9:10 AM, Shaibal Mitra <shaibal.mi...@csi.cuny.edu> wrote: > > 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: bounce-120008119-11143...@list.cornell.edu > [bounce-120008119-11143...@list.cornell.edu] on behalf of Peter Reisfeld > [drpi...@yahoo.com] > Sent: Wednesday, December 23, 2015 12:59 AM > To: NYSbirds-L@cornell.edu > 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/nysbirds-l@cornell.edu/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/nysbirds-l@cornell.edu/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/ > > -- > -- 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/nysbirds-l@cornell.edu/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/ --
