Flyways and Byways for Dec. 11

In the video game "Angry Birds," players help cartoon birds retake eggs that have been captured by hungry green pigs. It's a simple-sounding but addicting game that quickly becomes a highly entertaining and complex adventure.

The game simulates the behaviors and attitudes of the avian dramas we witness in our own backyards. Of course, there are no green pigs to contend with, but our backyard birds have to be on constant lookout for interlopers and predators.

Each spring, our resident birds, as well as those returning from southern migratory grounds, carve out individual territories that often must be defended over and over.

You have probably seen numerous pushing-and-shoving matches among different species as they feed together in the morning and late afternoon. Especially quarrelsome among their own species, house sparrows continually jockey for position on the feeder perch and never seem to learn to defer to the top gun.

Mate selection in the spring can be particularly aggressive when males, testy and tenacious, work to attract a partner and repel other suitors. The battle among males can go on for days until the female chooses her future mate.

Perhaps some of the angriest bouts occur when birds must drive away predators. When a red-shouldered or red-tailed hawk cruises through our neighborhoods, crows often begin mobbing and pursuing the raptor until it leaves. Small songbirds often will angrily pester an owl, even when it's perched and unthreatening.

A deadly backyard predator, the family cat, is often the target of avian ire. A prolific killer of birds, cats draw immediate attention, which triggers the flight of most small birds. Larger species, such as northern mockingbirds and blue jays, will attack a feline intruder with repeated dives over its head and noisy, menacing calls.

The noisiest fights tend to occur when an intruder, by guile or carelessness, approaches a nest with eggs or hatchlings.

I once watched a pair of brown thrashers mount a blistering attack against a small black snake climbing in a tree toward their nest. Intimidated, it gave up and dropped to the ground.

Colonial species, too, are ferocious in nesting defense. A few years ago, I accidentally approached a black tern breeding colony in Idaho and was attacked by a flock of very angry birds.

In cyberspace, you can help angry birds rescue their eggs at http://chrome.angrybirds.com.