Late yesterday afternoon, the clamor of chickadees, punctuated with a
few nuthatch calls, revealed the presence of a N. shrike on the
bluff-side edge of the small lake at Crosby Park. The chickadees
surrounded the shrike at a fairly close distance, flitting nimbly away
as the shrike moved casually through upper branches, stopping to perch
here and there.
It reminded me of crows mobbing a Great-horned owl, and raised the
same questions. Aside from the species-survival value of a warning
system, isn't this risky behavior for the individual birds? Do they
engage in it selectively, as when, for example, they've witnessed the
predator has just eaten, and is unlikely to hunt again? Is such a
racket likely to drive off a predator for its ability to foil a sneak
attack? Are they using the "safety in numbers" concept to confuse and
tire the predator?
I wish I'd had more time to follow the course of events.
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