Cooper's hawks swoop through our suburban yard every month or so, making passes at our feeder birds. The hawk knows a good hunting opportunity when it sees one.

A reader recently wrote to ask me what she could do about a family of these hawks raising havoc in her yard. Her feeder birds, she said, had been driven away by one adult Cooper's hawk and three of its young, recently fledged from a neighborhood nest.

Well, I told her, there is no immediate solution. Predators are part of the scheme of things, that old food chain story, hawks in this case a link higher than doves or chickadees.

Eventually, the hawks leave, either to find more productive hunting or to migrate. And next year, those young birds surviving would establish their own territories (odds are that two or three of four yearlings will die before next spring for one reason or another).

Cooper's hawks are common nesters in wooded areas, city and suburb included. They are inconspicuous birds most of the time, quietly going about their business. You might never notice one until it does its fighter-plane routine in your yard.

This bird is built for woodlands, with short, rounded wings and a fairly long tail. These features make it highly maneuverable, able to follow the twists and turns of prey amid branches. The hawk hunts from a concealed perch, approaching low and fast, using bushes or small trees to hide its flight.

It will take birds up to the size of doves or even crows, a species its own size. It also takes small mammals. It will typically take immature birds and mammals when available, creatures less experienced with the threat.

It doesn't succeed each time it attacks, captures averaging perhaps once in 10 tries. The prey birds in our yard either scatter or go motionless at first sight of the hawk. If one bird freezes, they all do. I have yet to see a Cooper's hunt successfully.

We won't see feeder activity again until the hawk is well and long gone.

This hawk, like other raptors, is a necessary part of the system that maintains balance in nature (not considering, of course, the imbalance we provide). Some of the birds that hawks capture are a bit slower than others of their species, perhaps less experienced, but lesser in some way.

Defects in survival mechanisms are best not passed to offspring. Continuation of the species, not the individual, is what is important.

About half of the songbirds that hatched this summer will not make it to their first birthday. Mortality is high, for many reasons other than the Cooper's hawk. If all chickadees survived each year to breed, the seven or eight in a clutch, we would soon be knee deep in chickadees. Chickadee habitat would not support that number.

And so, we have Cooper's hawks hunting at our feeders, helping thin the population, doing their job.

Lifelong birder Jim Williams can be reached at