AUG. 31, HERE is what seems to me to be a definitive analysis of this series of photos from Mathew Hunter.
1. My first impressions were of little doubt this was a Sharp-shinned Hawk (SSHA). The wing shape against the fence looks typical SSHA, short, wide, angled. The head looks small. The legs look really wire thin. The heavy barring is more typical of SSHA. However, a fence like this where I live is typically just under 4 ft tall, so that wire spacing would be 3 or so inches, making this a larger bird. Hmmmm.
So, let’s dive in for more analysis…
(a) Wheeler and Clark (North American Raptors) give length measurements defined as from the top of the head to the tip of the tail (slightly different than museum measurements). The first photo appears to show the bird taking up about 6 vertical spaces. This would translate to 2″ x 6 = 12″ in length. Wheeler and Clark give length measurements of 9-11 for male and 11-13 inches for female Sharp-shinned Hawks; and 14-16 inches for male and 16-19 inches for female Cooper’s Hawks. Our estimate falls in the range of female Sharp-shinned Hawk.
(c) Wing chord is the distance from the front of the bent wing to the tip of the longest primary. With all the angles it is difficult to determine, but in the 2nd photo, I would estimate a wing chord of about 4-4.5 squares or 8-9 inches. From the third photo, the wing chord looks again to be about 4-4.5 squares, or 8-9 inches. BNA gives average measurements of males in Michigan ave 6.72 inches, females 7.9 inches; and roughly similar measures for breeding birds in Oregon. For Cooper’s Hawk, 8.9 inches for males and 10 inches for females. This test is inconclusive (and figures are only averages, not ranges). However, as previously explained, our estimates from this photo would be higher than actual, which would shove the real-life measurements lower, again toward a female Sharp-shinned Hawk.
Well, that’s what I see. 🙂
Here is an accipiter trying to cope with the real world and one of its more confusing elements, a fence. Millions of years of evolution did not prepare this bird for this obstacle.
These photos were shared by Shannon Rio and her husband, Kirk. Here’s her explanation: “Kirk and I were sitting on our cabin porch [near Klamath Lake] and he spotted this
coopers. It seemed confused by the fence. It could not get over this low fence. I kept quietly telling it that it is a coopers hawk, a slender agile mobile hawk that can slink thru anywhere but this young kid just was not interested in the ramblings of an older woman. Finally it hopped onto the top of the fence and took off. It was at the base of some shrubs that are the apex of major yellow warbling sounds. So, ok, about a half hour later, Kirk spots a Cooper in a nearby tree and then it is gone. Then a young yellow warbler goes to the top of the shrub and gives pathetic calls for quite a while. We were wondering where the coopers hawk was but perhaps it was full. Anyway, that is our story. Another day in bird paradise.”