Re: [cobirds] Boulder surprising hawk kill

Having worked on the Cape May Raptor Banding Project this past fall, I had many discussions with a variety of people about the diminishing Sharpie populations.  It's been a noticeable trend in the capture data and the hawkwatch count data that Sharpies have been decreasing steadily over the last decade or so while Cooper's Hawks have been steadily increasing.  One of the major theories for this among everyone I talked to was the increasing fragmentation of forested habitat.  It might be that Sharpies are more reliant on dense vegetation and canopy cover to catch their unwitting prey, while Coops have been able to adapt to an increasingly urbanized environment.  This is just a theory and I'd be interested to see whether any data has been collected to back this up, but there has definitely been a noticeable shift in the proportions of these two Accipiters in the east.  That being said, we did have Sharpies make multiple passes at the pigeons we used as lure birds.  They commonly landed on starlings (even the tiny males would go for a starling), but I believe we only ever had one female land on a pigeon long enough for us to trap her.  There was a relatively recent discussion on the weight-carrying capacity of Sharpies on the CFO Facebook page if anyone is interested.  

Good birding,

Casey Setash

Fort Collins

On Fri, Feb 27, 2015 at 11:00 AM, Leon Bright <urraca2@comcast.net> wrote:

COBirders,

One late spring a few years ago at our cabin in western Custer County (9,200 ft.) I witnessed an interesting episode involving a young Sharp-shinned Hawk.  I was watching a group of small passerines on my platform feeder when I saw them scatter in a panic.  I noticed a sharpie had just landed on a fence post close by.  After a while he (probable gender) left, and three Steller's Jays came to the feeder.  The sharpie returned to the post.  The jays didn't fly off but were very nervous, jumping and flitting around.  The hawk made a couple of feints and the jays left reluctantly.  With no prey in sight, the Sharpie left again.  A couple of hours later there were several Band-tailed Pigeons feeding when the hawk showed up again on the fence post.  The pigeons completely ignored the accipiter which, even though inexperienced, decided against any try at prey whose 13 ounces outweighed his five or less.  He left for the third time, not to return at least to my knowledge.

Leon Bright, Pueblo

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Casey Setash

Vice President, VT Student

Chapter of The Wildlife Society

Wildlife Science

Virginia Tech Class of 2014

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