A hearty “thank you” to all the folks who responded to my ID question concerning Sharp-shinned Hawk vs Cooper’s Hawk. I truly appreciate you taking the time to look at the photos and provide responses!
For the benefit of others, no one replied with any great certainty that the bird was absolutely one species or the other and all offered traits to consider and that might suggest one species or the other. As a result of all your comments I will certainly observe with a more educated view next time, and attempt to get certain photos that would help in making the ID. Ed’s parting comment of “I’m not sure” pretty much sums up my conclusion at this point.
And by the way, the article Ed references below is indeed interesting and enlightening…and comforting to know that I’m not alone in feeling challenged with this ID.
Thank you again!
From: <tweeters-bounces...> [mailto:<tweeters-bounces...>] On Behalf Of <falcophile...>
Sent: Monday, March 13, 2017 8:55 PM
To: tweeters <tweeters...>
Subject: [Tweeters] ACCIPITER ID
The perennial Sharpie vs Coop ID dilemma returns.
I highly recommend reading the Josh Hull et al. article cited below. At Golden Gate Raptor Observatory they tested their observers ID skills by releasing 988 accipiters that had just been trapped and banded. 23% of the male Cooper's Hawks were incorrectly called female Sharp-shins. Note that these are high-level (rabid) hawk watchers.
Hull, JM, AM Fish, JJ Keane, SR Mori, BN Sacks & AC Hull 2010 “Estimation of Species Identification Error: Implications for Raptor Migration Counts and Trend Estimation,” J. Wildlife Management. 74(6):1326-1334.
After banding over 500 Cooper's Hawks and 150 Sharp-shins since 2000, I find myself much more comfortable saying "I'm not sure."