By Spike Knuth
Virginia Department of Game and Inland Fisheries
Issue: February, 1989
Virginia's owls are quiet hunters that attack with sudden swiftness on silent wings. They hunt by sound or by sight with special sensitive ears and eyes that are specially designed for low light conditions. In addition to their extraordinary vision and hearing, they have soft, downy plumage enabling almost soundless flight.
Owls seek seclusion during the day, although some northern owls - the hawk owl, snowy owl and short-eared owl - will hunt in daylight. Both the eyes and ears of owls are remarkable. In the darkness their pupils can be dilated almost to the width of the eye allowing much light in, like the widest opening of a camera lens. The pupils contract to a small speck when exposed to intense light. The eyes of owls have more rods and cones (receptor cells) which render them color blind but gives them superior vision in poor light. Their eyes are situated in front of a flat face giving it a wider range of vision. They also have binocular vision, giving a three dimensional effect necessary for distance determination. Of course to dive on prey in the dark requires that distances must be judged accurately and quickly. The ears of owls are as equally remarkable. This is especially true of barn owls which can locate and catch prey in total darkness.
There are 20 different species of owls in the United States; eight in Virginia. The smallest at 5 and 1/4 inches is the elf owl of the Southwestern deserts. The great gray owl, a boreal forest species, is the largest length-wise, measuring 24 to 33 inches with a 60 inch wing span. The great gray is more heavily feathered than other big owls and is not the biggest weight-wise.
Of Virginia species, the saw whet owl, which winters here, is seven inches long, while the common screech owl measures about eight inches in length. The short-eared owl is another winter resident of Virginia and will be found in open country such as fresh and saltwater marshes or open fields. The long-eared owl is a slender owl that inhabits woodlands and thickets.
Snowy owls are cyclic winter transients to Virginia. These large white owls are usually found in open country such as coastal sand dunes or farmland posts and haystacks. They measure 20 to 27 inches in length and are daytime hunters.
The great-horned owl epitomizes the owl family and is often referred to as the "tiger of the sky" or "cat owl." They measure 18 to 25 inches in length and along with the snowy owl are probably the heaviest owls. The barred owl is another very common owl of Virginia woodlands. Its call has more notes than most owls and is most likely to be heard calling back and forth at night.
The barn owl is the only owl with the white heart-shaped face. It is long-legged, knock-kneed and has a monkey-like face. They measure 14 to 20 inches and, as their name implies, lives in barns, sheds, or other man-made structures. Studies are being conducted on the effectiveness of man-made nesting boxes with the barn owl through the Nongame and Endangered Species Program. Barn owl nesting habits and sites are being studied and many young owls have been banded. Some of the owls have had radios affixed and their movements are being monitored by radio telemetry.