I had a couple hours to kill in Bellevue yesterday so I wandered over to the
Bellevue Botanical garden. I sat and watched a chickadee working on a nest
hole, carrying beakfuls of chips 15 feet away to leave no trace of its
excavation. A robin did its alarm call and the chickadee froze on the side
of the dead tree and moments later a Coopers hawk zoomed past. Within
seconds the hawk was out of view but the chickadee stayed completely still.
After about a minute and a half the hawk returned, zooming back the other
direction and covering much of the same ground again, passing the still
frozen chickadee. After this pass the chickadee went back to work only a few
seconds after the hawk passed out of view, and the bird of prey did not
reappear. So it seemed to me that the chickadee expected the hawk to double
back and stayed still until it did.

Today in my own yard, I saw the same return route flight behavior of a
Coopers Hawk as it passed by my bird feeder. It passed the feeder, zoomed
out of view, then returned about 2 minutes later for a second pass going the
other direction. I did not know this was a hunting technique of Coopers
hawks, thanks to the Chickadee for bringing it to my awareness. I wonder if
hawks do this in places where they expect to find prey, such a feeder or a
brushy clearing? And I wonder how many prey birds are hip to this trick and
if so, how they learn it?

Rob Sandelin
Naturalist, Writer, Teacher
Snohomish County WA