Owl

Strigidae

External appearances

Owls have large forward-facing eyes and ears, a hawk-like beak, and usually a conspicuous circle of feathers around each eye called a facial disk. Although owls have binocular vision, their large eyes are fixed in their sockets, and they must turn their entire head to change views.

Related Topics:
Hawk - Beak - Binocular vision

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Owls are far-sighted, and are unable to clearly see anything within a few inches of their eyes. However, their vision, particularly in low light, is incredibly good.

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Many owls can also hunt by sound in total darkness. Different species of owls make different sounds, one of which is the widely recognizable drawn-out "hoo" sound. The facial disc helps to funnel the sound of rodents to their ears, which are widely spaced. In some species, they are placed asymmetrically, for better directional location.

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Despite their appearances, owls are more closely related to the nightjars (Caprimulgiformes) than to the diurnal predators in the order Falconiformes. Some taxonomists place the nightjars in the same order as owls, as in the Sibley-Ahlquist taxonomy.

Related Topics:
Nightjar - Falconiformes - Order - Sibley-Ahlquist taxonomy

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The owls' powerful clawed feet and sharp beak enable them tear their prey to pieces before eating, although most items are swallowed whole. Their muffled wings and dull feathers allow them to fly almost silently and unseen.

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Scientists studying the diets of owls are helped by their habit of disgorging the indigestible parts of their prey (bones, scales, fur, etc.) in the form of pellets. These "owl pellets" are often sold by companies to schools to be dissected by students as a lesson in biology and ecology, because they are plentiful and easy to interpret.

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Owl eggs are white and almost spherical, and range in number from a few to a dozen dependent on species. Their nests are crudely built and may be in trees, underground burrows or barns and caves.

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Most owls are nocturnal, but several, including the pygmy owls (Glaucidium), are crepuscular, or twilight active, hunting mainly at dawn and dusk. A few owls, such as the Burrowing Owl (Speotyto cunicularia) and the Short-eared Owl (Asio flammeus), are also active during the day.

Related Topics:
Pygmy owl - Dawn - Dusk - Burrowing Owl - Short-eared Owl

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The smallest owls include the pygmy owls, some of which are only 13 cm (5.1 in) long, have a 32-cm (12.6-in) wingspan, and weigh only 50 g (1.76 oz). The largest owls are the eagle owls, the Eurasian Eagle Owl Bubo bubo and Verreaux's Eagle Owl B. lacteus, which may reach 71 cm (28 in) long, have a wingspan of just over 2 m (6.6 ft), and weigh about 4 kg (almost 9 lb).

Related Topics:
Eagle owls - Eurasian Eagle Owl - Verreaux's Eagle Owl

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• ORDER STRIGIFORMES
• Family Tytonidae: barn owls, 12 to 18 species
• Family Strigidae: typical owls, about 195 species.
• Proposed family Phodilidae: one or two species (currently included in Tytonidae)