Birds of the Western Slope December 5, 2012

Male KestrelKestrels

I've been concerned with the identification of these small raptors for months, in hopes that when they appear in our valley for winter I'd be more adept at identifying the sexes. And here they are — I counted seven on the way to town.

Female KestrelCompare the photos from AnimalDiversity.org, University of Michigan. The male has blue on his wings. The tail is barred at the tip, but is plain rufous otherwise. In contrast, the female has no blue and an obviously barred tail. These birds are also noted for the black streaks down the face, called "whiskers."

With a wingspan of about 22 inches, these birds are only about nine inches long (a bit less than a robin), and weigh about four ounces. They've been called "sparrow hawks" but they're clearly too small for that! Grasshopper hawk is more like it!

They're often seen perched on power lines, waiting for prey: insects of all kinds, rodents and small reptiles (note the small snake in the female's talons). They will hover above an area where prey might occur, such as a newly plowed field. This "wind hover" is actually a controlled stall with the bird moving its wings to match the prevailing wind. Quite a feat!

Both parents build the minimal nest in a tree cavity, along a cliff or in a nest box. They incubate the four or five eggs for a month. The chicks are immobile, downy, with eyes closed and must be fed.

Kestrels summer and nest to our north, winter into Panama, and are regularly seen in the United States. But it seems to me that they're more abundant during the winter months in our area. They appear to be about the size of a robin, but are usually sitting still on a power line. Keep an eye out for these colorful little raptors.

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