A Mobbing: Patterns in the Sky
Starlings and a Cooper's Hawk
October 18, 2005


While Sue and I were walking in the game land just north of Cooper's Pond, we saw a spectacular mobbing of an immature Cooper's hawk by hundreds of starlings.

At the time, I wasn't sure whether it was a Cooper's hawk or what the mobbing birds were, but Dan Ombalski of the Tussey Mountain Hawkwatch kindly identified both species for me. He had the following to say about the hawk:

    The accipiter as seen in [the photo below] shows (1) a prominent head projection in front of the leading edge of the wings, (2) a moderately chunky body, (3) a slightly rounded tail, and (4) the breast streaking stops rather abruptly midway on the underside of the bird. All point to an immature Cooper's hawk.

Immature Cooper's hawk and starlings (detail)

The above photo is a detail from the following, which shows the mass of surrounding starlings.

Although the starlings, below, look like they're at a flat level, they formed a cone with a few birds in front and the remainder following, with all the birds keeping their position order.

Immature Cooper's hawk and starlings

Whichever way the hawk turned, the starlings followed.

Immature Cooper's hawk and starlings

Unfortunately, the lens I was using was too much of a telephoto to capture the entire contingent of starlings. However, they were considerate enough to allow some side views, which show the height of the cone.
Side view of mobbing

It is as if the Cooper's hawk were slicing through the starlings.
Side view of mobbing

And a final view of the Cooper's hawk, who is remarkably beautiful.
Immature Cooper's hawk

Along with the main group of starlings were two smaller groups of forty to fifty birds each flying nearby. The encounter ended when the Cooper's hawk stopped trying to gain altitude but soared down into one of the smaller flocks. And then they all disappeared behind the trees.

Photo note: I used a Pentax *ist D, with the SMC reflex 400-600mm lens at the 600mm end.  

A reverse mobbing  |   Bald eagle flight   |   Spring Hawkwatch at Tussey Mountain

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