Sunday, September 22, 2013

Watchbirds

Or German Shepherds of the Bird World
Or How to Keep Cats out of Your Yard

Keeping cats out of our yard and away from the feathered morsels at the bird feeders [sigh] is a continuing, preoccupation, as our neighbor's two darling kittens have grown up to be lethal bird catchers. After some experimentation (yelling, arm waving, chasing, paper snapping), I've found that consistent watering with the Super Soaker convinces them to skip our backyard in the search for prey. In a new development, our next-door neighbor's sweet little kitten has developed her own unhealthy fascination with the bird feeder. Much as I hate doing it, I bird murders even worse, so treat that kitty to a super soak every time I see her in the backyard. [Update. The kitty, named Kira, has learned to visit me while I'm gardening in the front yard and entirely avoid the back. Who says cats can't be trained?]

Fortunately, I have help. Bertram, Corvina, and Ned turn out to be 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 gave it up 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!

No comments: