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Family Strigidae, Typical owls. 161 sp. WW. 18 sp. breed in N.Am.
Comprised of 3 groups: larger owls, usually with ear tufts (Bubo and Asio); the large to medium forest owls (Surni and Strix); and the small owls (Otus, Megascops, Glaucidium, Athene, Aegolius).
Owls are primarily nocturnal raptors but are NOT related to hawks. Like other raptors, female owls are significantly larger than males. Owls have a large compressed head with enormous forward-directed eyes that provide instantaneous binocular vision. The eyes are fixed in their sockets, requiring the owl to turn its head to change the direction of view. The nictitating membrane or third eyelid is specially developed to shield the highly sensitive retina from bright light. Their plumage is cryptically coloured. The very soft contour feathers and comb-like leading edge and fringed trailing edge of the flight feathers allow for an entirely silent flight which increases the probability that the owl’s approach will not be detected by their prey while at the same time increasing its ability to hear the sounds of its prey. Many species have feathered facial discs which have an acoustical function in gathering and concentrating sound waves like a parabolic reflector. Owls ears, although completely hidden under feathers are also very large and partially covered by flaps of skin which are framed in small contour feathers. In many species the right and left openings differ in size, shape, and location to increase the binaural efficiency in locating prey by sound. Food is swallowed whole and strong stomach juices digest over 95% of the flesh. The bones, claws, fur, feathers and insect chitin which are not digestible, are mixed with mucous in the gizzard to form a pellet and egested.

Distribution, abundance and breeding varies widely in response to local populations of their small mammal prey. Rodent-eating raptors show up to 5-fold variations in breeding success in association with annual fluctuations in prey density. Depending on the stage at which they occur, effects of food shortages can be manifest through non-laying, small clutches, egg desertion, poor chick growth and survival as well as loss of weight and reduced survival prospects for adults. Most owls begin incubation before the clutch is complete, staggering hatching over several days. Asynchronous hatching can be regarded as an adaptation to an unpredictable food supply enabling all young to survive in times of plenty, but ensuring rapid reduction of the brood to an appropriate size in times of scarcity.

Great Horned Owl

Visitors 13
1 photos
Created 13-Nov-13
Modified 13-Nov-13
Great Horned Owl

Snowy Owl

Visitors 20
14 photos
Created 10-Feb-14
Modified 10-Feb-14
Snowy Owl

Short-eared Owl

Visitors 5
3 photos
Created 19-Jan-14
Modified 19-Jan-14
Short-eared Owl

Long-eared Owl

Visitors 7
3 photos
Created 21-Jan-14
Modified 21-Jan-14
Long-eared Owl

Great Gray Owl

Visitors 11
5 photos
Created 30-Jan-14
Modified 30-Jan-14
Great Gray Owl

Barred Owl

Visitors 9
2 photos
Created 22-Jan-14
Modified 22-Jan-14
Barred Owl

San Isidro Mystery Owl

Visitors 5
2 photos
Created 30-Jan-14
Modified 30-Jan-14
San Isidro Mystery Owl

Northern Hawk Owl

Visitors 9
12 photos
Created 6-Feb-14
Modified 6-Feb-14
Northern Hawk Owl

Western Screech Owl

Visitors 2
1 photos
Created 30-Jan-14
Modified 30-Jan-14
Western Screech Owl

Northern Saw-whet Owl

Visitors 13
2 photos
Created 20-Dec-13
Modified 20-Dec-13
Northern Saw-whet Owl

Boreal Owl

Visitors 16
3 photos
Created 22-Dec-13
Modified 22-Dec-13
Boreal Owl

Burrowing Owl

Visitors 6
6 photos
Created 19-Jan-14
Modified 19-Jan-14
Burrowing Owl