[cobirds] Wheeler guide solves Boulder Co. buteo mystery

On Tuesday while trying to re-find previously reported Pinon Jays on Boulder CR 71N near Lyons, I spotted an interesting looking raptor perched on a Ponderosa Pine. a fortuitous pull-off allowed me to park and glass the bird which had a streaked underside and an interesting face pattern. As I reached for my camera, however, the bird flew and perched behind my truck.

With camera in hand, I was able to slip out of the truck and get a couple of photos before the bird flew. 

Scrutinizing the photos at home, I was puzzled by the bird's appearance. The white above the eye did not form a superciliary I had hoped for to confirm a Northern Goshawk. The white marks on the back did not form the scapular V of a Red-tailed Hawk, nor did the head appear to fit the usual Red-tail pattern.

After consulting the usual Sibley and National Geo field guides, I pulled Brian Wheeler's recent Birds of Prey of the West: A Field Guide from the shelf. Following Brian's advice to focus on the head, I finally landed on juvenile or immature Harlan's Hawk. The bird was unlike any Harlan's I have seen in Colorado, but Harlan's, like other Red-tails, is a very variable taxa. Though Wheeler's field guide can be intimidating, this is the second time I have found a puzzling plumage in his field guide that is not illustrated in other guides. 

Chuck Hundertmark

Lafayette, CO