Tuesday, February 24, 2009

Greater Redpoll ID confirmed! - 23 Feb 2009

A big thanks to all of you kind folks for replying to my previous post. I've gotten positive confirmation from Ron Pittaway and Michel Gosselin regarding the photos, and a nice banding summary from Allen regarding Redpoll measurements.

- Jerry

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Jerry,

Last winter I helped out a couple times at a banding station in Kalamazoo County where they banded 1700+ redpolls. I handled several birds that were likely "rostrata". There are currently only about a dozen specimens of rostrata from Michigan, and I am planning on writing a short paper on this sometime soon, to be published in Michigan Birds and Natural History.

The rostrata redpolls were indeed larger, weighing between 17-21 grams, while the flammea redpolls weighed between 11-14 grams. For comparison, American Goldfinches weigh 12-14 grams, while American Tree Sparrows weigh 16-22 grams. The upperparts of the rostrata redpolls appeared on average darker than on the flammea redpolls. And, most obvious, the black on the face/throat was noticeably more extensive in the rostrata redpolls. There was also a difference in bill measurements, and a shape difference that was detectable in-hand but may not be in the field. Additional photos of the bill and face of your bird would be helpful.

Allen T. Chartier
amazilia1@comcast.net
Inkster, Michigan, USA

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Hi Jerry,

This is Ron Pittaway. I looked at your photos. It is a "Greater" Common Redpoll (rostrata). For a second opinion, I sent the photos to Michel Gosselin of the Canadian Museum of Nature. Michel confirmed the identification.

Best wishes,

Ron
Toronto ON

1 comment:

Cathy Carroll said...

Great bird, Jerry. Thanks for bringing this species variation to our attention. Cathy

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