Barn Owl (Tyto alba)
Order: Strigiformes, Family: Tytonidae
Palearctic, Nearctic, Oriental, Ethiopian, Neotropical, Australian: The Barn owl is found on every continent except Antarctica. In the Americas, barn owls inhabit all of South America and all of North America except Canada. In Europe, the species ranges from southern Spain to southern Sweden and east to Russia. It also is found throughout Africa, except for in the Sahara.
I. GEOGRAPHIC RANGE
II. PHYSICAL CHARACTERISTICS
- Palearctic, Nearctic, Oriental, Ethiopian, Neotropical, Australian: The Barn owl is found on every continent except Antarctica. In the Americas, barn owls inhabit all of South America and all of North America except Canada. In Europe, the species ranges from southern Spain to southern Sweden and east to Russia. It also is found throughout Africa, except for in the Sahara.
III. FOOD HABITS
- The species is a medium-sized owl with long legs that are sparsely feathered down to the grey toes. The head is large and rounded without ear tufts. The barn owl has rounded wings and a short tail that is covered with white or light brown, downy feathers. The upperside of the bird is a light brown while the underside is a greyish white. The barn owl is very striking in appearance.
- The barn owl is a nocturnal predator that consumes small birds, but it prefers small mammals such as mice, voles, and shrews. Barn owls begin hunting alone one hour after sunset. As an aid for detecting movement in grassland, they have developed highly specialized low-light vision. When hunting in complete darkness, however, the owl relies on its acute hearing to capture prey. The barn owl is the the most accurate bird at locating prey by sound. Another trait that adds to its hunting success is its downy feathers, which help to muffle the sound of its movement. An owl can approach its prey virtually undetected. The barn owl attack its prey in low flights (1.5m-4.5 meters above the ground), capture the prey with its feet, and nip through the back of the skull with the bill. Then the prey is swallowed whole.
- Due to the short life span of the species (2 years on average), most individuals breed only once or twice. A pair is usually mates for life; however, there have been cases of polygyny. The male initiates courtship by a series of advertising calls, and then sexual chases follow with the male in pursuit of the female. During the chase, both the male and the female screech. Moth flights (male hovers above a perched female for several seconds, dangling his feet in front of her) are also a common method of courtship.
- Copulation occurs every few minutes during the nest site search. Both sexes crouch down in front of each other to solicit copulation. The male mounts the female, grasps her neck, and balances with spread wings. Copulation continues with decreasing frequency throughout incubation and chick rearing.
- Couples often use an old nest that have been occupied for decades rather than buiding a new one. The female lays four to seven solid white eggs in a dark space surrounded by pellets. She then incubates them until early May. After the owlets are 60 days old, they are able to hunt for themselves.
- When the species is not breeding, it is solitary or in pairs. It typically roosts in tree cavities, cliff crevices, or in riverbanks, but it can also be found roosting in many human structures such as barns, nest boxes, and churches. Barn owls are such efficient hunters that it is suspected that they spend much time loafing. The species is only partially migratory, with northern populations flying south during the winter months. When facing an intruder, the owl spreads its wings and tilts them so that their dorsal surface is towards the intruder. It then sways its head back and forth. This threat display is accompanied with hissing and billstraps that are given with the eyes squinted. If the intruder persists, the owl falls on its back and strikes with its feet.
VII. ECONOMIC IMPORTANCE FOR HUMANS
- Barn owls occupy a vast range of habitats from rural to urban, but they prefer warm climates with mild winters. Nearby open grassland is essential, however, for hunting. Barn owls are almost never found in deep forests or mountains.
- Biomes: temperate forest & rainforest, temperate grassland, desert, tropical rainforest, tropical deciduous forest, tropical scrub forest, tropical savanna and grasslands.
- The barn has long helped farmers by keeping the rodent population down.
IX. OTHER COMMENTS
- Status: special concern
- The barn owl has now gained legal protection as an endangered species or as a "special concern" species in several states. Declines in the barn owl population are directly related to climatic changes, pesticides, and changing agricultural techniques.
- A change of climate in northern regions is causing snow to last for longer periods making winter survival difficult for the species. Unlike other birds, barn owls do not store extra fat in their tissues that help them survive harsh winter weather. Many owls die during freezing weather or are too weak to breed in the following spring. Pesticides have also contributed to the demise of the species. For some unknown reason the barn owl suffers more severe effects from consuming pesticides than other species of owls. These pesticides are often responsible for eggshell thinning in females. With the average lifespan of an owl being two years, the reproduction process is already slow without the complications of weak eggshells. The last major factor limiting population growth is modern agricultural methods. The traditional farm has changed immensly in the 50 years. There is no longer an adequate amount of farm structures for nesting and farm land can no longer support a sufficient amount of rodents. The barn owl population, however, is not declining everywhere.
- Barn owls make a "khurrew" noise rather than a "hoot" like most other owls. The ears are asymetrical, with one on the forehead area and the other level with the nostril. They are extremely sensitive, and they can be closed by small feathered flaps if the noise level is too disturbing.