Hawk

This is my originally posted and probably incorrect analysis:

This was a "sleeper." The photo looks very much like an immature Red-tailed Hawk. I confess I don't know much about immatures of light morph "Harlan's" Red-tailed Hawks suggested by Bill Clark, but the light morph of that race is an extraordinary rarity anywhere in California. I'm only aware of a handful of sightings of adults, and no immatures have been documented in the state.

This bird was photographed at Valley Ford, Sonoma County, 25 November 1982 by Nancy Conzett. That was a month during which there was an extraordinary late influx of Broad-winged Hawks into Northern California, and an obvious Broad-winged Hawk was seen and photographed associating with this mystery bird.

The main hint suggesting that our mystery bird is not a Red-tailed Hawk is the short wing extension, with the wing-tips reaching only about half way down the tail. On Red-tails, especially of the Western race, the wing-tips reach all the way to the tip of the tail. Also the face pattern is stronger than most, but not all Red-tails. The underpart pattern is typical of Red-tail, but also matched by some Broad-wings which can show a strong belly-band contrasting with a white chest.

Another difference, that has not been previously mentioned is the pattern on the secondaries and tertials. These are diffusely barred on Red-tailed Hawk and solid brown on Broad-wing. This is clearer on the original photo than it it is on my computer monitor. Unfortunately the scanning process made the image much too dark above and I was unable to correct for this without making the whole image appear washed out..

The size is difficult to assess from a single photo of a bird sitting on a wire, but photos of Red-tails sitting on similar cables appear relatively much more massive. The mystery bird strikes me as quite petite and slim. This slim small appearance probably caused one contributor to suggest the bird might be a Merlin which would have a more boldly marked breast; different face pattern and no spotting on the upperwings.

Broad-wing has fewer tail bands than Red-tail. This is difficult to assess on the screen image, but the original photo seems to show only four or five even-width bands. In all of these features, the photo suggests Broad-winged Hawk which is what I still think it is.

One correspondent mentioned the possibility of Swainson's Hawk which does not have the pale spotting on the upper-wing as shown by our mystery bird.