The Comparison Of Diets Of Owl Essay

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The Comparison Of Diets Of Owl Essay, Research Paper Comparing the Feeding Habits of Barn Owls and Screech Owls Background Owls are comprised of two closely related families in the avian order Strigiformes-the barn owls, or Tytonidae, and the typical owls, or Strigidae. Owls are relatively large birds, with a big head and short neck, a hooked beak, talons adapted to seize prey, and soft, dense plumage adapted for swift yet almost silent flight. Owls have large eyes located on the front of their face. The eyes are almost fixed in their sockets, so that the entire head must be rotated or bobbed for the gaze to be shifted and for distance to be assessed. Owls have excellent hearing and very large ears, although these are covered by feathers and are not readily seen. The ears are

placed asymmetrically on the head to aid in detecting the location of distant, almost silent prey. Their sense of hearing is probably also aided by their facial disk, which helps to focus sound waves onto the ears. An owl’s sense of hearing is so acute that it can accurately strike its prey in total darkness, following the squeaks and rustling sounds created by a small mammal in motion. The sex of an owl is not easy to distinguish, although typically, female owls are larger than males. Owls begin to incubate their eggs as they are laid. When hatching occurs it is sequential, and different-sized young are in the nest at the same time. During years when prey is relatively abundant, all of the young will have enough to eat and may survive. In leaner years, however, only the

largest young may be fed adequately. (Egan, T. (1994). Oregon, Foiling Forecasters, Thrives as it protects owls. New York Times, October 11, pg A1, A19) Most owls are nocturnal predators, mostly feeding on small mammals and birds, and sometimes on small reptiles, frogs, larger insects, and earthworms. A few specialized owls feed on fish. Owls are known to change their food preference, depending on local or seasonal availability. Most owls do not digest the fur, feathers, or bones of their prey, and they regurgitate these items as pellets, which can be collected at roosts and examined to learn about the feeding habits of these birds. Barn owls The barn owls are a distinctive-looking group, with a characteristic like facial disk of stiff, white feathers, dark eyes, long legs that

distinguish them from typical owls. All barn owls are nocturnal predators, and their prey consists mostly of small mammals. There are nine species of barn owls (genus Tyto) and two species of closely related grass owls (genus Phodilus). The most familiar species is the barn owl ( Tyto alba). The barn owl is one of the most widely distributed species of birds, occurring on all continents except Antarctica. The barn owl is the only representative of this family in the Americas, occurring uncommonly through most of the United States and in much of Central and South America. The barn owl nests in cavities in trees and in barns and abandoned buildings, and it hunts at dusk and at night over marshes, prairies, fields, and farmyards. Screech Owl The screech-owl( Otus kennicotti) is a

relatively familiar species in woodlands of temperate regions. This 8.5″(22 cm) long species occurs in several color phases-grey, red, and brown-and it nests in cavities and sometimes nestboxes. Owl Pellets The average owl pellet contains bones and other non-digestible items such as hair and feathers. After the bird has eaten its prey; the prey is digested into the gizzard where grinding occurs. After grinding the bird’s gizzard makes a ball of the indigestible material, is expelled by mouth. An average owl can produce an average of one to two pellets a day. John Day, Oregon The John Day area is considered a semi-arid desert region. John Day, Oregon is located at Latitude 44.418427 and Longitude -118.949399, which is 125 miles south of Pendleton, Oregon in Eastern Oregon. A