Saturday, 2 February 2013

Burrowing Owl

order : Strigiformes      Genus & Species : Strigidae     Family : Athene cunicularia

The burrowing owl is primarily a ground-level operator, nesting underground and running after prey, but it is also a clever hunter, hovering in flight above its target. One of the few owls adapted for land dwelling, the burrowing owl is an ultra-efficient daytime hunter, attacking prey on land or in the air.They found in grassland from British Columbia in Canada, through western U.S. and central Mexico, to Tierra del Fuego in South America. 

Habitat : The burrowing owl’s range includes prairies and plains. Level, open, dry vegetation — found in Canada, the western U.S., Mexico and the treeless pampas of Central and South America — provides hiding sites for the young, while allowing full vision for adults. The male usually “borrows” an abandoned burrow of a badger, prairie dog or, in South America, viscacha, but he can excavate his own, too. The burrow slopes gradually and then turns abruptly right or left. This ensures that the nest chamber at the end of the tunnel is as dark as it can be, an essential feature for added protection of eggs and young.A network of branching tunnels provides foodstorage areas and escape routes. Raised mounds, fences or rocks make perfect perches for observing prey. Migratory only in its northern range, the owl often overwinters in the south, setting up permanent residency to keep the burrow clean. 
Food & Hunting : Most of the year, the owl hunts from sunrise to sunset. In the spring, it pursues small mammals at low-light periods, especially during the cool early evening. In the summer heat, these small mammals retreat underground to stay cool, and the burrowing owl then stalks larger insects, such as locusts, grasshoppers, dragonflies and dung beetles. The burrowing owl runs on its long legs and snatches smaller prey with one foot. With broad wings unfolded, the owl can also swoop in for the kill from a perch near the nesting hole.The owl quietly hovers, taking deadly aim at a mouse, cottontail or even a ground squirrel that is equal to its own size. Feathers, hair and bones, which are all indigestible, accumulate in the owl’s gizzard and are regurgitated in the form of pellets. 
Behavior : Considered comical because of its bowing display, the male burrowing owl dips its body forward as it sings, cu-coo, cu-coo, a mellow love song that is one of approximately 17 vocalizations.This song, repeated every hour at night during courtship, is also emitted for territorial defense. Bobbing up and down for a better view, the burrowing owl guards the immediate area of its burrow, but allows feeding in commonly shared areas by adjacent owl pairs. Females rasp when begging for or receiving food from the male during incubation, or when passing food to the young.The burrowing owl utters a buzzing “rattle” resembling the sound of a rattlesnake when disturbed, or when cornered by predators such as badgers or snakes. Burrowing owls line their nest chambers with 1–2" of dung, which provides insulation and also masks the odor of the nest to protect the young from hungry predators. 
Breeding : Before initiating courtship, the male owl selects a burrow and prepares a nest. Up to 10' long and 6" wide, the tunnel ends with a dark 12–18" wide nesting cavity, lined with dung and feathers. Once it is complete, the courtship ritual begins. The pair mates after an extended period of songs, billing, mutual nibbling of the head feathers and food presentation. Since burrowing owls do not form permanent bonds, the mating cycle is repeated annually. After mating, the female lays one egg every other day. Incubation starts with the first egg; the parents take turns incubating the 6–11 eggs.The female’s absence is brief, however, because the male brings her food. The grayish-white owlets weigh 0.3 oz. each and hatch at intervals; the oldest can be two weeks older than the youngest. 

Bill : The burrowing owl breaks its prey’s neck with sharp blows from its large hooked beak. 
Eyes : The large pupils and corneas gather as much light as possible during the low-light conditions of sunrise and sunset.The lemon-yellow irises distinguish the burrowing owl from nocturnal owls, which have brown irises that are invisible during night hunting. 
Claws : With two toes in front and two toes directed backward, the owl grasps prey with sharp talons fully spread. The powerful claws also dig dirt and kick it backward during burrow excavation. 
Legs : Legs, longer than those of nocturnal owls, enable the burrowing owl to walk easily across grassland in search of insects. 

Weight : 5–5.5 oz.
Length : 7-9.5"
Wingspan : 20-24"
Sexual Maturity : 1 year
Breeding Season : March –August

The burrowing owl’s species name, cunicularia, comes from the Latin word cunicularius, meaning “a miner or burrower.”

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