Just got the current issue of the Journal of Field Ornithology (vol. 85, no. 4, December 2014). I figure this is not a journal that most birders check for ID articles so I thought I would draw attention to an article in it: "Simple technique for distinguishing Yellow-bellied Flycatchers from Cordilleran and Pacific-slope flycatchers by M. J. Baumann, S. C. Galen, N. D. Pederson and C. C. Witt. Pp. 391-396. Anyone interested should read the article for all the details, many of which involve measurements that can only be done in the hand, but there is one character that can be used to distinguish Yellow-bellied Flycatcher from "Western Flycatcher" (the complex composed of Cordilleran and Pacific-slope flys.). It involves the space on the folded wing between the lower wing bar and the start of the pale fringes on the secondaries. This space is much larger in the Yellow-bellied than in the "Western". I pulled out a few field guides from my bookshelf to see if it was distinguishable in published illustrations. I found it was apparent in the photos in Kenn Kaufman's Birds of North America (at least in the first edition that I have). It was also obvious in Dave Sibley's paintings of these species in his Second Edition of the Sibley Guide to Birds (I didn't check the first edition). The authors of the Journal of Field Ornithology article tested their technique on 113 museum specimens that had been identified based on locality. They found their technique correctly place 112 of the specimens. One specimen labeled as a Yellow-bellied Flycatcher that had been collected in Illinois was identified as a "Western Flycatcher" by their technique. Amazingly, when the mtDNA of this specimen was examined, the specimen proved to be a "Western Flycatcher", the first for the complex for Illinois!
Distinguishing a Yellow-bellied Fly from a "Western Fly" has not come up yet in New York, but hey, you never know. Joe DiCostanzo www.greatgullisland.org <http://www.greatgullisland.org/> www.inwoodbirder.blogspot.com -- 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/ --
