Classification and Range
Western screech owls are part of the family Strigidae or "typical" owls. They are one of the smaller owls found within this family with ear tufts and well-developed facial discs. There are approximately 36 species in the genus Megascops and, in North America, three species of screech owls; eastern (M. asio), western (M. kennicoti) and whiskered (M. trichopsis). In total, there are 18 recognized subspecies of western screech owls. Western screech owls inhabit open woodlands, wooded stream and river banks throughout Pacific Coast mountain ranges in Canada and from the Pacific Coast to the Rocky Mountains in North America.
Due to their wide distribution, western screech owls use a variety of habitats. Habitat can vary from tropical coast lowlands to desert habitats in the south, to temperate rain forests in the North. In general, these owls prefer partially open country with many deciduous trees around, particularly oaks, sycamores and riparian hardwoods.
TWestern screech owls are small owls measuring from 6.5 to 8 inches (16-20 cm) in length with a wingspan of 20 to 22 inches (52-56 cm). Their body is gray to brownish-gray in color with a streaked chest and belly. They have black bills and yellow eyes. They have prominent ear tufts when they are raised. Like many other raptor species, females and males are similar in color.
Western screech owls are nocturnal. Their vocalizations consist of a series of short whistles that increase in tempo near the end. They sometimes will use a double trill tone when alarmed..
In both the wild and captivity, screech owls can live to about 13 years.
In the wild: The western screech owls hunt small mammals, insects, snakes, lizards, frogs, small birds and even crayfish and scorpions. In winter, when prey is scarce, screech owls have even been seen attacking larger birds such as domestic ducks and pheasants. In summer, these birds can often be seen hunting insects and moths around street lamps.
At the zoo: Mice, insects and coturnix quail.
It is believed that female and male western screech owls mate for life. They vocalize heavily at the beginning of the breeding season and will engage in mutual head-preening when a potential mate is found. The breeding season is short, typically lasting from March to May. Nest sites in the western screech owl vary greatly according to habitat. Favorite nest choices include natural tree hollows and cavities excavated by woodpeckers. They lay two to seven eggs that are incubated mainly by the female for 30 days.
Young chicks are ready to leave the nest at 30-32 days of age and the success rate of reaching fledging age is quite high, around 73% of eggs hatched in the nest. Being hit by automobiles is a large mortality factor in the first year of life in western screech owls.
Screech or no Screech?
The western screech owl has two distinct calls, neither of which are a screech. The first call is often described as a bouncing ball. It is a series of even and distinct notes, which start slowly then accelerate and runs together, like a ball that bounces more quickly as the bounce gets smaller. The second call, used when a male and female are dueting, is a short trill followed quickly by a longer one.
Location at the Zoo
A western screech owl is housed at the Raptor Center at the zoo. He is missing a wing and is only visible to the public when being handled or when used in education programs. Great horned, spectacled and barred owls can be seen at the raptor center along with a Harris' hawk and turkey vulture. Great gray owls can be found in the Temperate Forest adjacent to Bug World and snowy owls are on display in the Northern Trail exhibit.
In many areas, screech owls have suffered substantial habitat losses. On the other hand, relatively abundant food supply and probable increased protection from great horned owls has allowed screech owls to become more abundant in city parks and suburban areas.
Many raptor species are in trouble. Human-caused changes in land use are escalating, and this affects the habitats and migratory corridors required by some raptors for survival. Vast forests are being removed for timber and other paper products, and industrial emissions are polluting water and air resources. Critical shoreline and riparian zone habitats are being rapidly converted by expanding human communities and agricultural needs. Shooting and trapping are also lowering raptor numbers. It's only a matter of time until more raptor species may face extinction, unless we take measures to protect their habitats.
Humans need raptors. Here are only a few of the benefits raptors provide:
- Raptors help keep animal populations in balance.
- Raptors consume many animals that humans consider as pests, including mice, rats and destructive species of insects. This helps to control disease and damage to crops.
- As top predators of their food chain, raptors are an indicator species of the overall health of the ecosystem in which they live.
- Of equal importance, witnessing wild raptors enriches each of our lives. Imagine what life would be like if we could no longer hear the haunting evening call of the owl.
How You Can Help!
Efforts to save threatened and endangered raptors require cooperation and support at international, national, regional and individual levels. You can help in this cause. Join and become active in Woodland Park Zoo and other conservation organizations. Recycle forest products. Eliminate or reduce pesticide use. Support breeding programs for endangered birds of prey at zoos and other animal care organizations. Let your elected representatives know your views about the conservation of migratory birds and their wild habitats.
Contact Woodland Park Zoo at firstname.lastname@example.org to find out how you can support conservation efforts at the zoo or visit our How You Can Help section.
Sources and Suggested Reading
Burton, J.A. (editor). 1992 (third ed.). Owls of the World: Their Evolution, Structure and Ecology. E.P. Dutton, New York, NY. 216 p.
Jarvis, Kila and Denver W. Holt. 1996. Owls: Whoo Are They? Mountain Press Publishing Company, Missoula, MT. 59 p.
Zoobooks. 1992. Owls. Wildlife Education, Ltd., San Diego, CA. 17 p.