Friday, December 4, 2009

Warmer Temps and a Hint of Variety

While checking out the South Boulder Creek Trail at lunch today I did see a Red-tailed Hawk, (I would have been alarmed if I hadn't at this point), but I was fortunate to see a bit of a mix as well. The Great Blue Heron above was cutting behind a tree, but the more overcast sky did more to accent the longer white feathers on the breast.

I had a good long look at two American Tree Sparrows who were eating seeds near some scrubby brush. The breast spot, pronounced white wingbars, and white edging on the tail all help to identify this species as compared to a Chipping or other sparrow.

Another pair of solid field marks, if they can be seen, are the bi-color bill, and rufous eye-line. Note the yellow on the bottom half of the bill, and the closer view of the face below.

I find that in the field the facial differences between the two are tough to distinguish as they bounce around in heavy cover. Perhaps the easiest way to keep the two similar species straight in Colorado is to remember that the Chipping Sparrow breeds here in the summer, and the American Tree Sparrow has returned to its wintering grounds from the far north.

As always the colors of an American Kestrel are a good sight on returning to the parking lot.
Have a safe and fun weekend, I am off to a CFO (Colorado Field Ornithologists) trip at Chatfield tomorrow, and may try to get up to Ft. Collins to try to find the White-winged Crossbills Sunday. They were confirmed still in the area today, so we'll see.

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