[cobirds] Chatfield , Douglas County

I agree with John's assessment on the age and sex -- first year male. Aging terminology is fraught with challenges and errors--even in many field guides. Note that juveniles have one generation of feathers. Once a bird starts replacing feathers, I would not call a bird a juvenile. This is one advantage of using simpler terminology like first year versus juvenile and first basic and first alternate, which require more understanding of molt. 

Anyway one of the best ways to age this bird as a first year is by the two generations of feathers in the wing coverts--best appreciated by the molt contrast in the greater coverts. Now don't be scared by this--this just means that wing coverts look different from each other and this case conspicuously so. Note how the outer greater coverts have narrow white tips (these are retained juvenile feathers) while the inners are newer fresher and orangey. You can see similar sorts of things to age some birds in your backyard (House Finch, juncos) where first-year birds show similar contrast (often more subtle than in Brambling). Steve Howell has an excellent book on molt that makes it pretty easy to understand. 

Anyway, great bird and great thanks to Mike and Cynthia for getting the word out! Excellent observation, indeed! I started birding right after the last two in CO, so this makes our Thanksgiving trip even more spectacular. It was great to see so many old friends too! Thanks to all. 

On iPhone so sorry for any odd typos or incomprehensible statements, which as likely as not have nothing to do with the phone; but it is always good to have a scapegoat!

Happy Thanksgiving and good birding,

Chris

Chris Wood, eBird project leader

Ithaca, NY, but still really a Colorado boy. 

On Tuesday, November 20, 2012, John D wrote:

Co birders :

     After the excitement of seeing the Brambling , we found a juvenile Red-throated Loon at Chatfield seen close to the dam wall from the handicapped fishing pier around midday and a Rusty Blackbird at the Plum creek delta which on a second visit at 2:30 pm increased to 2 birds ,male and immature female feeding along the muddy shoreline.

Re the Brambling and using my Collins Field Guide to Birds of Britain and Europe ( in my view still the best bird guide in the world ) I am inclining to a juvenile male on basis of strong orange of breast and upper scapulars , blackish tip to yellow bill , head pattern shows black fringes to grey ( yes grey not gray ) face feathers , little to no orange colouration around black flank spots and I thought that the white rump was tinged yellow ( mark of a juvenile ) but I would appreciate confirmation of this if anybody got a good photo of the rump. Any way I will be sending my photos to my friends in england for their comments.

 

John Drummond

Monument 

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Chris Wood

eBird & Neotropical Birds Project Leader
Cornell Lab of Ornithology, Ithaca, New York
http://ebird.org
http://neotropical.birds.cornell.edu

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