On Saturday, December 27th, Bob DeCandido and I paid a visit to the Cassin's Kingbird at Floyd Bennett Field, obtaining several photos, among them:
http://photo.net/photodb/photo?photo_id=17935335 http://photo.net/photodb/photo?photo_id=17935268 http://photo.net/photodb/photo?photo_id=17935269 An examination of the photos reveals that the bird is an adult male. Pyle discusses Cassin's Kingbird in his "Identification Guide to North American Birds: Part 1" with illustrations of the wing formula (Figure 171), the shape of the outermost primary (p10) by sex and age (Figure 173), and a comparison of the shape of P6 in adult male and female Cassin's Kingbirds (Figure 174). Here's a close-up of the outer primaries of the Floyd Bennett Field Cassin's Kingbird: http://photo.net/photodb/photo?photo_id=17941419 Here we can see that not only is the outermost primary less deeply notched than that of the similar Western Kingbird (Figure 176 in Pyle), but P6 is narrower than that of an adult female Cassin's Kingbird (Figure 174). The Slater Museum of Natural History Wing & Tail Image Collection is also useful in this regard. Here's the dorsal surface of an adult male Cassin's Kingbird from the Slater collection (specimen 78061a): http://digitalcollections.pugetsound.edu/cdm/singleitem/collection/slaterwing/id/13198/rec/1 And the dorsal surface of a male Western Kingbird [not an adult] from the Slater collection (specimen 17298a) for comparison. P10 is an adult feathers and has a very long and narrow sickle shape: http://digitalcollections.pugetsound.edu/cdm/singleitem/collection/slaterwing/id/12466/rec/1 We tend to think that birds found outside their normal range are young birds, but both the Cassin's Kingbird and Couch's Kingbird are adult males. One wonders where they spent the previous fall and winter. Deborah Allen -- 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/ --
