Megascops kennicottii, commonly known as the Western screech owl, is a small grey owl belonging to the family Strigidae (Alden 1998). Until the 1980’s the Western screech owl and the similar Eastern screech owl (Megasopsis asio) were considered the same species, but the two are now seen as distinct (Kaufmann 2017). M. kennicottii is native to western North America, with its most common range consisting of coastal British Columbia, Washington, and Oregon. It can also be found in Idaho, California, Nevada, Colorado, Utah, Arizona, New Mexico, and Mexico, but its dispersal is much more patchy and uncommon in these areas (Cannings et al. 2017). Megascops kennicottii, can most commonly be found inhabiting coastal deciduous forests below six thousand feet (1,828 meters) in elevation. However, they are also known to occupy other biomes, such as the non-extreme deserts of Arizona and parks and suburbs in populated areas (All About Birds 2015). They are essentially non-migratory, with a limited range of around three hundred kilometers (Cannings et al. 2017).
Megascops kennicottii has a distinctly short, stocky body, with an average length of 20-25 cm.. It has a wingspan of around 60 cm and usually weighs from 100-300 g. (All About Birds 2015). Females are typically about four percent larger than their male counterparts. The external features of Megascops kennicottii vary slightly depending on their native region, but generally it has brown or grey-brown plumage. The coastal populations of the Pacific Northwest are more diverse in plumage, with seven percent of individuals colored a reddish brown. Its dorsal body feathers are grey or brown with a dark central streak and thin horizontal bars, while its ventral feathers are whitish but also have the dark central streak and horizontal bars. Its remiges (wing flight feathers) and rectrices (tail feathers) are also a brown or dark grey color with lighter, whitish bars, and its face is often pale, ranging from white to pale-brown or pale-grey with dark lateral borders. M. kennicottii is most distinguishable by its lemon-yellow eyes. Its legs and feet are mostly covered with feathers and its toe scales and claws are yellowish to greyish in color, becoming darker toward the tips. Its bill also begins yellowish and darkens to a bluish gray toward the tip (Cannings et al. 2017).
Despite its name, the Western screech owl does not screech, but instead has a call consisting of a series of accelerating hoots with a rhythm similar to that of a bouncing ball. Primarily nocturnal, it hunts a wide variety of small prey including rodents, amphibians, birds, fish, worms, and insects (Cannings et al. 2017). These owls practice the “sit and wait style” of hunting, patiently waiting and watching from above and swooping in on prey (All About Birds 2015). Wild Megascops kennicottii typically live one to eight years. It has been estimated that they begin breeding as one-year-old adults, and attempt to nest yearly. They are monogamous breeders, with females typically laying three to five eggs. They are referred to as “cavity nesters” because they nest in holes of a tree where branches have broken off, rather than piling sticks and leaves together (Cannings et al. 2017).
The western screech owl (Megascops kennicottii) is a small owl native to North and Central America, closely related to the eastern screech owl. The scientific name commemorates the American naturalist Robert Kennicott.
Length averages 22 cm (8.7 in), wingspan 55 cm (22 in), and weight 143 g (5.0 oz). Weight ranges from 88 to 220 g (3.1 to 7.8 oz).[3] Females are larger than males and northern populations are notably larger than southern populations.[4] Adults are larger than whiskered screech owls, with larger feet and a more streaked plumage pattern.
There are several morphs: brown Pacific, grey Pacific, Great Plains, Mojave, and Mexican. All have either brown or dark gray plumage with streaking on the underparts. There is no red morph. This brown and gray streaky coloring allows the owl to camouflage with trees and hide from predators.[5]
They have a round head with ear tufts, yellow eyes, and a yellowish bill. Their appearance is quite similar to whiskered and eastern screech owls, so it is best to identify them by their calls. They were previously considered to be the same species as the eastern screech owl.[6]
The primary call is an accelerating series of short whistles at an increasing tempo or a short then long trill falling slightly at end. Other calls: barking and chuckling, similar to the eastern screech owl.[6] They also make a high pitched screech.
The two primary songs for the Western Screen Owl are the bounce and double trill. In a recent study, researchers utilizes sonographic analysis of tape-recorded vocalizations to analyze whether the songs differ in male and females and if so, how accurately could songs be classified by sex. It was discovered that on average, male bounce songs were ~30% lower in frequency than bounce songs of females. However, song duration, note duration, number of notes per bout, and internote duration did not differ. For trill songs, males were also significantly lower in frequency compared to those of females. In addition, female double trill songs had greater internet distances in the leading portion. [7]
The western screech owl is native to Canada, United States, Mexico, Guatemala, El Salvador, Honduras, Costa Rica, and Nicaragua.[1] Its habitat includes temperate forests, subtropical and tropical montane forests, shrubland, desert, rural fields, and even suburban parks and gardens.[1]
Western screech owls are permanent residents of the northwest region of North and Central America, breeding in open woods or mixed woods at forest edges. When attracting a female, a male brings her food and creates a series of clicking noises. During courtship, the pair preens each other's feathers and sing duets with each other.[8][9] Once a male and female become a pair, they produce a clutch of 2-7 eggs.[8][5] The male delivers food to the female as she broods, and once the eggs hatch, the male continues to provide food which the female feeds to the owlets.[8][5] Both mates then protect their owlets by guarding their tree cavity from dangers such as snakes, jays, and crows. The female is inseparable from her young for their first three weeks of life, but afterwards she joins the male in hunting for two weeks until the baby owls are ready to leave the nest.[8][10]
Rather than living in traditional nests, Western Screech Owls reside in cavities in trees, banks, or cliffs.[11][8][10][12] Of these cavities, the tree species vary. They include, but are not limited to oaks, willows, cottonwoods, and cacti.[8][5] These cavities are around 1 feet in diameter and up to 1.5 feet deep.[8]
More often than not, these cavities are found by the male owl and were made by natural causes or other species such as woodpeckers. They could nest in these cavities for several years.[8][13][9]
The cavities serve not only as shelter, but also as a camouflaging device against potential predators.[8][13][10] The height for these nests range from approximately 10 to 30 feet above ground.[14][12]
These nocturnal birds wait on perches to swoop down on unsuspecting prey; they may also catch insects in flight. They are active at dawn, night, or near dusk, using their excellent hearing and night vision to locate prey. Their diet consists mainly of small mammals (such as mice, rats, flying squirrels, and bats), birds (such as northern cardinals and white-throated sparrows), and large insects (such as cicadas); however they are opportunistic predators, even taking to small trout, annelid worms, scorpions, crayfish, reptiles, amphibians, and smaller birds.[5][15][16] Their diet varies based on the season and where exactly they reside.[5][14][10][15]
Motion-activated cameras have photographed the birds eagerly scavenging a road-kill opossum. They have also been known to hunt mallard ducks and cottontail rabbits, occasionally. Hatching of their young is synchronized with the spring migration of birds; after migrants pass through screech-owls take fledglings of local birds.
Although the western screech owl is slowly declining in the Pacific Northwest, the species is considered "of low conservation concern" due to their nocturnality and general ability to live alongside humans in surrounding trees. Their population is estimated to be 180,000 according to the Avian Conservation Assessment Database Scores.[8] In areas densely populated by people, human noise can be a disturbance to their creation of nest cavities and human devastation of forests negatively impacts their habitat. Climate disasters such as fires and heat waves can endanger their livelihood. Humans have made efforts to provide manmade shelter, such as nest boxes, for Western Screech-Owls. The owls have proven to be receptive to these habitats.[17][5][9]
There are 9 recognized subspecies:[18]
Captive bird at the Desert Museum
Nest hole
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Perched
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Western screech owl in the Pacific Northwest The western screech owl (Megascops kennicottii) is a small owl native to North and Central America, closely related to the eastern screech owl. The scientific name commemorates the American naturalist Robert Kennicott.
