Their small size, excellent camouflage, unfussy nesting habits, and varied diet make Eastern and Western Screech-Owls successful survivors. The eastern birds adjust well to human presence. In fact, suburbs may provide more prey, milder climates, and fewer predators than rural areas. Western Screech-Owls choose higher, drier habitats. Territories of these two species, formerly classified as one, can overlap. The two species are also known to hybridize. Both Barred Owls and Great Horned Owls prey on the much smaller Screech-Owls.
Range: Eastern Screech-Owls reside year-round primarily east of the Rocky Mountains. Western Screech-Owls are found in the southwestern, western, and northwestern states up into Alaska.
Field marks: These diminutive owls are about 9 inches tall with 20-inch wingspans and strongly barred underparts. Females are slightly larger than males. Characteristic ear tufts are lacking in the young. Although Eastern and Western Screech-Owls closely resemble each other, the bills are yellow-greenish in eastern owls and black in western owls. Eastern owls are gray or reddish brown; western owls are gray or brown.
Voice: Eastern birds utter a mournful tremulous, descending trilling call, described as a whinny. Western birds emit a series of short whistles described as a bouncing ball call. Both birds “bark” when alarmed.
Feeding: Screech owls begin feeding after dusk. These nocturnal generalists eat night-flying insects, small mammals, and birds alike, then regurgitate pellets of feathers, fur, and bones.
Eastern Screech-Owls begin nesting in February in southern states but may wait until July in far northern habitats. Provide birdbaths for drinking and bathing and nest boxes for seasonal nesting, as well as for roosting and storing prey year-round. Western Screech-Owls use nest boxes less readily than their eastern counterparts. (Data are for the more widely studied Eastern Screech-Owl.)
Nesting habits: Males bring food to females at potential nest sites. Once chosen, the male guards and defends the area surrounding the nest site.
Eggs: Usually four to five white or cream-colored eggs.
Egg-laying: he first few eggs are often laid two days apart, then one per day.
Incubation: 26 days. Female incubates; both parents feed young.
Days to fledge: 28 days after hatching.
Although biologist Fred Gehlbach also studies Western Screech-Owls in Arizona, he knows Eastern Screech-Owls best. Upon moving to central Texas to teach at Baylor University in the early 1960s, he was intrigued by a pair of owls popping out of a fox squirrel box. He has been studying the nesting habits of rural and suburban screech owls and telling their stories ever since. Gehlbach examined the owls’ natural tree cavity nests, created three different nest box designs, and tested them all. Outdoor plywood, pine, and cedar all worked well: “The more weathered the better,” notes Gehlbach, and an 8-inch-square floor size was “just fine.” Gehlbach also found that these owls fare better in suburbia than rural areas. “Life is easier there,” he explains. Spacious lawns and open spaces are good places to hunt, and backyard bird feeders offer up small-feathered prey. Gehlbach’s book, Eastern Screech Owl: Life History, Ecology, and Behavior in the Suburbs and Countryside, is in its second printing (2008).
• One 1″x10″x8′ cypress (used here) or cedar board (3/4″ thick)
• Two 1 1/2″x1 1/2″ exterior hinges with hinge screws
• Approximately thirty 2″ exterior-grade deck screws
1.Cut pieces according to the drawing. Measure and cut out the 3″ entrance hole on the front piece (be certain you measure up from the bottom 10″ to the bottom of the hole). Make four or five kerf cuts on the exterior of the box, the same width as the entrance hole. cuts are 1/2″ apart and 1/4″ deep.
2. Drill out 1/4″ drain holes on the floor piece. start assembly of pieces by laying out the back piece and placing the sides on it. Mark and predrill pieces accordingly. attach sides to the back piece. Predrill the floor piece and screw to sides.
3. Be certain to recess the floor piece 1/2″ from the bottom, to prevent water seepage into the nest cavity.
4. Attach the predrilled front piece to the sides and floor. Be sure that the front piece is aligned with the angle of the sides, as this allows for a tight fit of the roof.
5. Place the roof piece on top of the sides and make sure it’s centered.
6. Attach the hinges to the roof so that they are equal distance apart (approximately 1 1/2″ in from the edge of the roof). Attach the hinge to the back piece. drill mounting holes in the back piece.
7. The screech-owl nest box is ready to hang onto a tree or post or building. Opposite page: the nest box was attached to a tall, straight pine with two ¼” diameter, 4″ long galvanized lag screws driven into the back piece, with a washer between screws and board.
Shaded areas in sparse woods, streamside forests, farmland, suburban backyards, and city parks. Avoid facing the nest box north. Face the entry hole east or south where possible, as the birds like to sit in the entranceway (even during the day) to soak up sunlight.
Nesting materials: Add a couple of inches of wood chips or dry leaves.
Mounting: Attach to straight trees wider than the box or install on posts or buildings.
Height: About 10 feet high.