Smaller birds tend to be fast and agile, and they can move through the air as well as they can move on the ground — or even better. This makes them difficult prey to catch for most predators. The biggest threat to adult songbirds usually comes not from ground-based predators, but from hunting birds, especially Cooper's Hawks.
These handsome raptors can be found in the Tehachapi Mountains, particularly in the winter months, but some of them are here year-round. Cooper's Hawks (Accipiter cooperii) feed primarily on other birds, so by necessity they are incredible flyers: quick, maneuverable and fearless.
Cooper's Hawks have traditionally been birds of forest and woodlands, but they have been able to adapt to the leafy environments of suburbs and outlying homes, where ornamental trees mingle with native trees to create attractive habitat for songbirds.
Cooper's Hawks are also drawn to yards with bird feeders — not because the hawks eat seeds, of course, but they actively prey on the smaller birds that do. Cooper's Hawks catch birds both on the wing and on the ground, and the presence of a Cooper's Hawk can cause a sudden change in songbird behavior.
The chattering smaller birds usually fall silent immediately, so a sudden stillness among songbirds is often an indication that a hunting Cooper's Hawk is in the neighborhood. Birds that are perching in shrubs or trees will often remain motionless when they spot a hawk, while those that are more exposed will dive for cover in the thickest foliage they can find.
Cooper's Hawks will sometimes pursue songbirds right into a thicket in the quest for a meal, occasionally with disastrous results — I have found two different Cooper's Hawks fatally impaled on sharp broken branches, and Cooper's Hawks brought to wildlife rehab facilities are often suffering from broken wings or other injuries resulting from collisions with trees or buildings while chasing fleeing songbirds. They are such full throttle birds that even rehabilitation can be difficult, since they are prone to re-injury when caged.
There are three kinds of accipiter hawks that can be found in the Tehachapi Mountains: Goshawks, Cooper's Hawks, and Sharp-shinned Hawks. Cooper's are the midsize hawks, with the rarer Goshawks being bigger and the Sharpies the smallest of the three.
Cooper's Hawks and Sharp-shins can be difficult to distinguish, since they have very similar markings, as well as tremendous variation in plumage among different individuals — I can't think of two other North American birds that consistently offer a greater challenge in identification. The Cornell Lab's Project FeederWatch website offers some good tips in the subtle ways to distinguish between the two.
Cooper's Hawks are one of the bird species that has actually gotten easier to see in more recent decades — their numbers were much lower in the 1950s and 60s, when they were often shot as well as being adversely affected by DDT poisoning. With legal protection and better pesticide regulation, as well as their adaptation to hunting around houses, Cooper's Hawks are now a more common sight than they once were.
While they will take mice, chipmunks, squirrels and other mammals, Cooper's Hawks prey mostly on other birds, especially those that are slightly larger, like starlings, jays, doves, pigeons, quail, flickers, etc. It is partly because of these winged hunters that birds must remain so vigilant when they are foraging -- if they let their guard down, they may find themselves in the talons of a hungry Cooper's Hawk.
Have a good week.
Jon Hammond has written for Tehachapi News for more than 30 years. Send email to firstname.lastname@example.org.