Elementary Natural Science: Owls (1976)

People have long been fascinated by owls, though most owls are woodland dwellers. They live in nearly every type of environment from arid desert to arctic tundra. Owls in fact are found worldwide with over 15 species in the United States alone. The great horned owl occurs continentwide. This 3 to four lb giant is perhaps the most aggressive of all native owls and seems to wear an angry glare to prove it. Some call the horned owl the tiger of the air. The great horned, along with most other owls, is nocturnal, which means active at night. It appears to be well adapted to operate in darkness. Large, uniquely constructed eyes, 35 times more sensitive to light than ours, give it superb powers of night vision, and it flies quietly for attacks in the dark. The owl's wing feather on the left has a fringe, which the hawks on the right lacks. This fringe reduces wing noise. Fluffy body feathers also muffle sound. Keen hearing helps where vision fails. Large ears lie hidden beneath head feathers. Owls also have unusual feet. Most birds have three toes in front, one in back. The third talon of the owl is reversible for better gripping. This white-footed mouse is about to learn how efficient the great horned owl is as a nightigh hunter. By using its specially developed eyes and ears, the silent flying owl is able to see and capture the mouse in the dark. Like hawks, owls help control populations of rodents and other wildlife. But most owls work at night. The great horned owl is not choosy at meal time and eats a wide variety of prey, including rats, rabbits, fish, and insects. Even skunks are table fair for the great horned owl. Owls begin their lives in white nearly round eggs. Great horns lay one to four even before winter ends. The young wear a warm down coat for protection. Their home might be an old hawks or crow's nest. Since owls are poor carpenters, they use whatever housing is available. The top of a brokenoff tree works well, too. In northern regions, snow often rims the nursery. Despite such weather, great horns rarely migrate. Sometimes in areas offering few natural sites, they will nest even in man-made structures such as this. At night, the young become hungry and welcome room service from their mother. Though both parents hunt prey, only the female delivers it to the young. In the owl family, the female rules the roost because generally she is larger than her mate. Great horns in many areas nest during the spring migration of blackbirds, robins, and other song birds. These passing visitors offer the owls a plentiful source of food for the growing young. Here they are offered a meadowark. Several of them may be consumed in one night. The entire bird is eaten, bones, feathers and all. These 3-week old young will fledge or leave the nest in another 3 weeks and follow their parents until fall. Owls often bob and weave their heads like ancient far east dancers. Although owls have naturally good depth perception already, this exotic head dance helps them gauge distances even more precisely. If we were to design a better mouse trap, it might look like this. The barn owl is the mouse catching champion of the world. This aptly named bird often nests in barns. It also uses water towers, silos, church steeples, and a variety of other buildings in both rural and urban settings. Is there a place for them near your school? This monkeylike face is one that mice should fear. The barn owl's talons, attached to unusually long legs, are deadly enemies to mice. Four to six young comprise the average brood. The little mouse eaters may vary in size because owls often lay eggs several days apart, but incubation may start when the first egg is laid. The farmer counts himself lucky to have this tenant family since it helps control rodents on his land. After 8 weeks, the young fledge. For these inexperienced hunters, the first year will be hard, and starvation, disease, and accident will claim many. But some will survive to breed and continue the species. No one shares, and a rat goes down hole in a series of gulps. Think you'll make it? Of course, but with little room to spare. Such manners. These are pellets. They are compact masses of fur, feathers, bones, and certain other parts of prey. Owls regurgitate or spit up pellets to get rid of such matter which will not pass through the digestive tract. Researchers have found that pellets contain a record of an owl's diet. For instance, one recent study of barn owl pellets revealed that rodents provide 90% of the food for some individuals. This material came from the pellets found beneath the roost of one barn owl. One of North America's smallest owls is the sawette. Its tiny body, hidden beneath fluffy feathers, isn't much bigger than a bluebird's. Nonetheless, it is a mighty hunter, and white-footed mice should be careful in saw wet country. In summer, this owl's peculiar call may be heard chiefly in northern pine forests. It winters in our central states. The screech owl is another economized model. This 8-in bird occurs in towns, orchards, and wood lots of every continental state except Alaska. Members of the clan come in different colors, ranging from red to brown to gray. The broken pattern on the plumage of all color phases provides natural camouflage for daytime concealment. Like most small owls, the screech owl hides its nest inside a tree in a woodpecker hole or other natural cavity. These pint-sized predators are aggressive and might be called the wild cats of the air. During nesting season, they sometimes attack people who venture too near their nursery. The young are fed a variety of prey including mice, small song birds, reptiles, amphibians, and a collection of large insects that would delight an entomologist. People who talk about the hoot owl usually mean this one, the bard owl. Its familiar call may be heard in nearly any mature woodlands east of the Rockies. Its calls and those of other owls are usually related to courtship and territorial defense. Is its head on upside down? No. Owls have rubber bandlike necks that can twist 3/4 of a circle. B owls love water for bathing and hunting. They regularly eat fish, frogs, and crayfish in addition to small mammals and birds. Big brown eyes create a wise, gentle appearance. Though not especially intelligent, no owl is, the barred owl is mildtempered and might be called the teddy bear of the air. Still covered with down, the young can hardly fly when they leave the nest. The 5-in long elf owl of the southwestern deserts is our smallest owl. A prairie dog town might be home for the unusual burrowing owl. Members of this peculiar species nest underground. They often use deserted burrows of prairie dogs, badgers, and other hole digging mammals, but sometimes even dig their own. They live in the dry, short grass plains, which cover much of the West and a small portion of Florida. In favorite areas, they may concentrate together to form communities of a halfozen or more pairs. Burrowing owls commonly hunt while the sun is up. Contrary to legend, owls can see quite well in bright sunshine. But only a few, such as the burrowing owl, choose to be dal or day active. Favorite foods include a variety of insects and mice. The crow-sized shorthaired owl is another ground dweller, though it does not enter holes. The ear toughs from which it draws its name are small and hard to see. And why it or any other owl has them, no one knows for sure. The short-eared nests in open prairies and marshes, chiefly from our border states to well beyond the Arctic Circle. It winters in fields throughout the United States where it feeds heavily on mice. The tangled spruce woods of Alaska and Canada host another unusual member of the owl family, the hawk owl. Like a hawk, it often hunts during the day from high treetop perches which most owls shun. Adding to its hawk image also are its long tail, tilted rather than upright posture, and rather small eyes. The snowy owl lives even further north. This white giant occurs all across the treeless tundra surrounding the North Pole. It is one of the few birds capable of surviving the severe Arctic winter. It dresses warmly for the cold weather. Long feathers protect even the nostrils. The nest is merely a shallow dish scraped in the earth. Up to 10 eggs may be laid, though if food is scarce, not all the young will survive. The family run will have to grow quickly to beat winter's early arrival. During the summer months, nesting birds and fish often provide a great part of the diet. In winter, the owls must turn to lemmings and hairs, which do not migrate south. When these mammals are in short supply, the owls themselves must travel south in search of food, sometimes wandering as far as Louisiana. After spending months on the ground, they now seem to welcome the chance to perch high above the earth, even if it means sitting on a TV antenna. Owls as a group have been very successful. Their worst enemy is man and his machines. When he clears land for mining, agriculture, or housing, he often destroys hunting and nesting sites. He also kills the owl's prey with pesticides which may poison the hunter as well. In addition, man-reated accidents claim many, and some are shot along with hawks by thoughtless individuals who are unaware of the owl's special beauty and vital role in the natural world. Owls live as predators among nature's night prowlers. They help keep wildlife populations in balance and add unusual variety to the wild world. The next time you are out after dark, listen. Perhaps you will hear an owl busy patrolling the nighttime wildlife airways.