Sunday, September 22, 2013

Watchbirds

Crows are the German Shepherds of the bird world.

Keeping cats out of our yard and away from the feathered morsels at the bird feeders [sigh] is a continuing, un-favorite preoccupation of mine. First, one neighbor's two darling kittens turned into lethal bird catchers. After some experimentation (yelling, arm waving, chasing, paper snapping), I learned that consistent watering with the super soaker would convince them to skirt our yard in their search for prey. Now our next-door neighbor's sweet little kitten has developed his own unhealthy fascination with the bird feeder. I hate doing it, but hating bird murders even worse, I treat that kitty to a super soak every time I see him in the yard. (Update: The kitty and I have reached a settlement. He can hang out in the front yard, but not in the back.)

Fortunately, I have help. Bertram, Corvina, and Ned are watchbirds. They caw to let me know when there's a cat in the yard. There is no ignoring the noise, or mistaking it for anything but a demand for cat mitigation measures. At first, the crows cawed at cats hanging out in other yards, too, but stopped when they learned that their fuss only works for our yard.

Bertram warns the other yardbirds about a predatory cat. 

I thought this warning behavior might be unique to "my" crows, but a couple of weeks ago I watched while a crow cawed angrily at a bus that had collided with a seagull. The crow sat on the wire over the bus stop and cawed at the offending bus as well as every other bus that came during the 15 minutes I was standing there. Crows also take action towards predatory birds during nesting season. When hawks and eagles try to raid a crow's nest, crows flock in from the surrounding areas and gang up on the predators, hassling them until they give up and leave.

Dr. John Marzluff, at the University of Washington, is very interested in how crows share knowledge with one another about "dangerous humans," e.g., humans who have trapped and banded them for research and then released them. From my personal observations, though, it isn't just humans that crows mob, but anything that represents a danger -- a hawk, an eagle, a cat -- or even a bus. Crows are to other birds world like German Shepherds are to people: watchers, warners, and sometimes even attackers
You go, Bertram!

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