[Birdtalk] Crossbills by Ear

[Kristin Purdy]

Many of us who have reported White-winged Crossbills across the past few
weeks have included statements such as "there were no Red Crossbills
present, according to the calls I heard", or perhaps a flock did include
both species due to more than one call type detected. E-bird hosts an
excellent article by Matt Young from Cornell's Lab of Ornithology that
explains and demystifies the calls of both species. If you're wondering why
everyone is referring to the two species' calls or you're planning a
pilgrimage to the mountains to seek crossbills on your own, read this
article to help prepare:

http://ebird.org/content/ebird/news/introduction-to%20crossbill-vocalizations

Kris