American Kestrel

Western Screech Owl, a feisty little raptor

The Western Screech Owl (Otus kennicotti) breeds throughout the western U.S., from southern Canada to Baja California, and other parts of Mexico. This little owl is the fourth and smallest of the raptors I handle and interpret at the Arizona-Sonora Desert Museum. I’ve written previously about the Harris’ Hawk, the Barn Owl, and the American Kestrel. (I also handle snakes.)

Western screech owl

The Western Screech Owl has a body length of 8- to 10 inches, and a wingspan of 20- to 24 inches. (The infamous Cactus Ferruginous Pygmy Owl is slightly smaller.) The yellow eyes are very penetrating. When alert or excited, it raises some feathers on its head – “ear” tufts. The owl is usually gray and streaked with black and white (there is a red race). The only other owl in this region it may be confused with is the Elf Owl, which is much smaller (5 inches in length) and lacks the ear tufts. The screech owl’s toes are zygodactylous (two pointed forward, two pointing backwards). There’s a word for Scrabble fans.

Screech owls generally do not migrate. They are cavity nesters, so you might see one peeking out of a hole in a saguaro cactus. (They will also nest in boxes.) The female lays 4- to 6 eggs, each about 2- to 3 days apart. The chicks hatch after about 26 days and open their eyes after about a week. The female broods the chicks for two weeks while the male brings food. The chicks stay in the nest for about five weeks, all the time being fed by their parents. Life expectancy in the wild is 4- to 6 years, but captive birds are known to have reached an age of 18 years.

The Screech owl is a fierce predator and will attack prey much larger, relative to its size, in comparison with other owls. The screech owl will attack large Norway rats, mice, lizards, insects, smaller birds, scorpions, spiders, ground squirrels, and fish. Its normal habitat in the desert is the wooded areas near mountains, or along tree-lined rivers. In wooded areas, the owl’s dull color makes good camouflage.

Despite its name, the owl doesn’t screech. Instead, it has a series of trilling calls. Screech owls have keen hearing which help in capturing prey, but their hearing is not as specialized as that of the Barn Owl.

The American Kestrel, our smallest falcon

Kestrel-male-Warren-LynnThe American Kestrel (Falco sparverius) is the smallest falcon in North America. Males have bluish-gray on the head and wings and a rust-colored breast and back. Females have gray on the head only, and are generally speckled brown with dark bars. The body is about 10 inches long (females are larger) and its wingspan is less than two feet.

Kestrels feed on insects, lizards, small rodents, and other birds. They usually don’t pursue the prey, but wait on a perch to pounce on something that comes along. If no perches are available, the Kestrel can hover in the air.

Kestrels have sharp talons for seizing prey, but unlike hawks or eagles, falcons usually make a killing bite to the head or neck. A small triangular protrusion from the upper bill, called a tomial tooth, is designed to slip between vertebrae and sever the spinal cord of the prey animal.

Kestrels occur throughout the Americas in appropriate habitat such as edges of forests or fields, deserts and grasslands, and in city suburbs. They are cavity nesters, so may be observed in saguaro holes, cavities in cliff faces, broken tree limbs, or cavities in structures. In the city and suburbs, they favor yards with bird feeders. I’ve seen Kestrels snatch sparrows off a bird feeder in my yard.

A pair of Kestrels will defend a territory against other Kestrels, but during the winter, males and females may defend separate territories. Courtship happens in the spring and couples frequently re-mate. Males typically display a series of dives and produce a “klee” sound over the nesting area. Observers note that Kestrels mate much more frequently than would be necessary for egg fertilization. Imagine that. Besides the “klee” call during mating, Kestrels use a shrill “kee kee kee” alarm sound and there is also a chittering sound used between a mated pair.

Kestrel-femaile-Susan-Beebe

Kestrels generally produce one clutch per year with up to four eggs, each produced two-days apart. Incubation takes 30 days and the young chicks leave the nest after another 30 days. Life span in the wild is about 10 years.

Besides normal binocular vision, falcons have telescopic peripheral vision apparently due to a dimple in their retinas which focuses light. They use peripheral vision to scan the sky for predators and to search for prey when flying.

American Kestrels used to be called sparrow hawks. There are other falcons called kestrels, such as the European kestrel, but they are generally larger than the American Kestrel.

To see more photos of Kestrels, go here. For more information go here.