by Damian Fagan
Throughout the Southwest, the nocturnal call of the western screech owl, Megascops kennecotti, may be heard in wild or even residential areas. The call is very different from the generic hoot typically associated with owls. Instead, the call is a descending series of whistled notes that ends with a short trill. Some liken the call to a mournful whinny or a “bouncing ping-pong ball.” The western screech owl’s calls have little to do with screeching.
Megascops kennecotti is named for Robert Kennicott (1835 to 1866), an Illinois-born naturalist and explorer who collected owl specimens throughout Canada and Alaska. He suffered from poor health his entire life, finally dying of a heart attack in Alaska while working on a telegraph line survey.
The western screech owl’s range extends from Baja California and central Mexico northward through California and west Texas up to western Montana and western British Columbia and southeast Alaska. At one time, the western and the eastern screech owl were considered to be one species, but they have since been split into two separate species. The western screech owl’s range overlaps that of its relative, the whiskered screech owl, Otus trichopsis, which occurs in southern Arizona and into Mexico. Both species are often permanent residents throughout their common range, rarely migrating very far.
Western screech owls are “eared” owls like the great horned or long-eared owls. Their ear tufts are relatively short and spaced apart like those of the great horned owl. The tufts may be held erect or flattened depending upon the situation at hand. The real ear openings are located on the side of the head and are slightly offset from each other. This positioning enables the owl to use triangulation to trace sounds and locate potential prey at night.
The eight- to nine-inch tall western screech owl’s facial disk is bordered with black. The bird has an overall gray appearance, although those that live along the northwest coast have a reddish phase. The underside is striped and barred with dark feathers enabling the bird to blend in with its surroundings. On average, the female is larger than the male, although the plumage is similar for both sexes. Sometimes the yellow eyes with dark pupils are the first indication that a bird watcher may see of the bird as it perches quietly on a tree limb next to the trunk.
Mainly nocturnal, the western screech owl hunts primarily for a variety of mammalian and insect prey, although it may also take birds. Mice, shrews and insects make up a majority of its diet, but young wood rats, kangaroo rats, toads and scorpions may also be taken. With a 21- to 22-inch wingspan, the owl hunts from a perch and descends on its prey. It is not afraid of tackling prey that weigh as much as it does! Even though western screech owls are predators, they may themselves fall prey to other predators, including hawks, snakes, raccoons, skunks, weasels or even larger owls.
Like other owls, the western screech owl cannot digest bones or fur. It regurgitates those parts two to four times a day in the form of ¾- by 1 ½-inch pellets, which offer researchers clues to the bird’s diet.
During the breeding season, courting western screech owls may keep up a constant chatter of calls that sounds as if the birds are harmonizing. They may start calling in the winter. They will often respond to imitations of their calls.
In most of its range, the western screech owl nests in cavities in dead or live trees or stumps. In the Sonoran Desert, it may, like the whiskered screech owl, nest in cavities in saguaro cacti. Some of the cavities may be holes abandoned by woodpeckers or flickers. Other cavities may have formed at the rotted base of broken limbs. The western screech owl will also use nest boxes, especially in residential areas where potential nest trees have been cut down or trimmed for cosmetic reasons.
The female owl will lay two to eight white, rounded eggs. She does most of the incubating. The male brings food to her and the young. The incubation period lasts for about 26 days. Young birds make their first flight about 28 days after hatching. The young western screech owl, like the young of many other species of owls, is able to climb back up a tree trunk if it happens to leave the nest prematurely. The adults will continue to feed their young even though they have left the nest. The adults defend their nest sites furiously, with continual dives, beak-snapping and general havoc.
One year I followed Rich Levad, then a retired English teacher, through the suburbs and agricultural lands of Grand Junction, Colorado, on a survey for western screech owls. He and Tom Moran, a dentist, and several other birders initiated the survey after they had observed several of the birds during the annual, Audubon-sponsored Christmas Bird Count.
Levad and Moran systematically searched habitats, playing taped owl calls. They focused on areas with thick stands of cottonwoods, which often have natural cavities or woodpecker holes. They scouted residential areas and farmlands, as well. To their surprise, they had responses from 102 owls in different locations within the area over a month’s time.
Though not all of these owls were nesters, Levad and Moran deduced that they had found at least 18 breeding pairs. But to the birders’ disappointment, many of the trees in the nesting area were either being removed or were falling down. To replace lost nesting cavities, Levad and Moran and others started to erect nest boxesmore than 200 of them!
The nest boxes allowed the birders to easily resurvey the sites to look for activity. Even during the day, a western screech owl will show its face as it looks out its nest cavity. Using a ladder for access, the birders could easily lift the hinged lids of the nest boxes and check for nesting birds. For sites with young, Moran and others would return when the birds were old enough and affix a U. S. Fish and Wildlife Service identification band on the owls’ legs. These numbered bands, when relocated, could provide information about longevity or dispersal of the young.
Levad recorded wing and beak measurements, weights and sex for each of the juvenile fuzz balls he banded. Though the young were fairly docile, he reported that they still snapped their beaks and fluffed out their feathers to look as large and intimidating as possible.
Occasionally, the birders discovered that American kestrels, woodpeckers or even wood ducks had appropriated the nest boxes. But with enough natural and man-made boxes to go around, there was room in the valley for everyone.
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