Elementary Natural Science: Hawks (1977)

[music] [music] >> A wide variety of hawks occur in North America. They're distinguished by heavy hooked beaks and long sharp talons, which are the tools of their remarkable trade. Hawks hunt other creatures for a living. The red-tailed hawk is at home in woodlands, mountains, and even deserts across the nation. It feeds on mice and other small mammals. The red-tailed hawk and similar hawks are called buteos. Buteos have broad rounded wings, robust bodies, and wide fan tails. The red-tailed hawk builds a sturdy stick nest where one to three eggs are laid. The young are fed by the female who tears prey into bite-sized bits. 18 months will elapse before the chick sports the red tail of an adult. Overhead, the male guards the territory. Hawks sit atop the food chain and reproduce slowly. In the time red tails produce two young, a pair of mice might raise two dozen offspring. The hawks will consume some of the mice, helping curb their surpluses. This is part of the balance of nature. After 6 months, the young red-tailed hawk is on its own. It may now weigh 3 lb and have a wingspan of 4 ft. And with vision three to five times stronger than ours, it has no trouble spotting mice 50 yd away. Researchers believe the red-tailed hawk succeeds only once in every four hunting attempts. Other prey include squirrels and cottontails. Red-tailed hawks vary widely in color. Most are medium brown, but some are very dark. There are even a few rare pure white albinos. A common close relative of the red-tailed hawk is the slightly smaller red-shouldered hawk. It's found in lowlands and swamp forests, chiefly east of the Great Plains. The red-shouldered hawk also nests in upland woodlands, though it avoids the territory of its larger cousin. Notice the reddish-brown feathers on the adult's shoulder. The red-shouldered hawk usually hunts amphibians, reptiles, and small mammals and birds. The male arrives with a frog captured from a swamp. Do you think red-shouldered hawks greatly reduce the number of frogs? Or will they hurt snake populations? Remember, there are still many mice, even though mice are regularly hunted by these hawks. Farther north on the Arctic tundra, where there are no trees, we find another buteo, the rough-legged hawk. In size and habits, it closely resembles the red-tailed hawk, except that it perches on rocks instead of tree limbs. The carefully guarded nest is just a shallow depression on a cliff. Rough-legged hawks are named for the warm feathers they wear down to their toes. Winter's approach sends them south to the United States. The marsh hawk is another ground nester found in northern fields and marshes. The male wears pearl gray. The female dresses in brown. The marsh hawk is not a buteo, but a harrier. Like other harriers, it is slender and has long wings and a long tail. More than 75% of the marsh hawk's diet is mice. This 6-week-old youngster will leave its nest shortly just by wandering away. A third family of hawks are the accipiters. They have short rounded wings and long tails for high maneuverability. These high-strung predators hunt birds in thickets. The Cooper's hawk, an uncommon resident of the United States and Canada, is typical of accipiters. It catches starlings and other small birds by sneak attacks. An average Cooper's nestling eats 40 birds before it fledges or leaves the nest. Once it leaves the nest, it will consume about one bird per day. Do you think that these rare hawks eat too many birds? The sharp-shinned hawk closely resembles the Cooper's hawk. Both species often have favorite perches or butcher's blocks where they pluck their prey with all the care of a gourmet chef. Largest and perhaps fiercest of the accipiters is the goshawk. This rare bird, which lives in northern forests, is about the same size as the red-tailed hawk. But the goshawk has unusually big feet. It's a reckless hunter, sometimes crashing through thickets in pursuit of grouse and red squirrels, which are its favorite prey. The osprey is found worldwide near seacoasts and large rivers and lakes where it hunts almost exclusively for fish. This uncommon bird hovers high above the surface, then plunges suddenly, sometimes going completely underwater to get its prey. It's not unusual for osprey to catch fish weighing as much as 2 lb. And it's said that an osprey once drowned going after a record-breaking catch. But maybe that's just a fish story. North America's smallest and most numerous hawk is the kestrel. The drab female and colorful male are often seen perched on utility poles along highways. The bluejay-sized kestrel, or sparrow hawk, is a member of the falcon family. Like other falcons, it has long pointed wings, a large head, and a long tail. Falcons fly with choppy, powerful wingbeats and are famous for their speed. In late summer, the little kestrel often dines on grasshoppers. The famed peregrine falcon is probably the earth's fastest bird. In a dive, it can go 160 mph. The cliff-loving peregrine once nested on ledges throughout much of the world. Now, unfortunately, except in distant northern regions, it has disappeared from most of North America. Scientists believe that certain insecticides can be blamed for much of this loss. Today, scientists are experimenting with ways to bring the endangered peregrine back to some of the areas where it once lived. The peregrine hunts birds in flight. Using its massive feet, it attacks them in midair. At one time, the peregrine even hunted pigeons and sparrows in New York City where skyscrapers offered nesting sites. The name peregrine means wanderer, and someday these young may travel all the way to Argentina to winter. For thousands of years, man hunted with falcons. Falconry is still practiced in some areas today. The winged hunter is released to circle overhead. When prey flies below, the falcon stoops or dives, striking the unsuspecting bird with its feet. This pigeon may never see the falcon coming. Under favorable artificial conditions, the hawk usually is successful. However, in the wild, one observer reports that falcons make kills in fewer than one out of 10 tries. The hawk is brought back with a lure and food. One of the species most highly prized by falconers is the gyrfalcon. Nestlings such as these have reportedly sold for $10,000. Though happily, trade in birds of prey is against the law in most places. Gyrfalcons are the largest of the falcon clan and range in color from nearly black to a striking snow white. They nest on cliffs in the Arctic, which is home year-round. In this stark country, a pair may have a territory of 200 square miles. Note the choppy stroke of the falcon's long pointed wings. Gyrfalcons feed on both birds and mammals, which these nestlings will soon have to learn to catch for themselves. Eagles are included in the hawk family. They are buteos like the red-tailed hawk. North America has two species, including the golden eagle, named for the colorful hue of its neck feathers. This rare resident of remote western and northern regions feeds largely on small mammals such as ground squirrels and jackrabbits. The second eagle is our national emblem, the bald eagle. This impressive 10 to 12 lb bird has a wingspan of nearly 8 ft. The bald eagle builds a bulky treetop nest and may remodel it year after year until it weighs a ton or more. The bald eagle feeds chiefly on fish and rarely ventures far from water. While it is skillful at plucking prey from shallow depths, the eagle may simply scavenge dead fish. And to its discredit, it will also rob the osprey of a catch. For these reasons, Ben Franklin disagreed with the choice of our national emblem. He suggested the wild turkey. But few creatures appear to be as magnificent as the bald eagle. But unfortunately, the bald eagle is an endangered species. In the United States, it is now common only in Alaska and part of Florida. Poisons and human interference have been the eagles' most dangerous enemies. Many people are now trying to save the bald eagle and bring it back to places where it once lived. But this takes time because these large predators mature slowly. The young remain in the nest for 3 months and under their parents' care through fall. It takes at least 4 years before the dark brown youngster finally gets the white markings of an adult and is ready to breed. As a mature bird, the eagle may live for 10 years with its impressive form adding grace and beauty to our nation's skies. As wild hunters, hawks face many natural dangers, but people are their greatest enemies. Thoughtless individuals shoot many and our chemicals poison others. And as we carve up the wilderness to gather resources and make room for housing and agriculture, we destroy habitat. When habitat goes, hawks disappear with it. But hopefully, the red-tailed hawk and its relatives will always find wild living room. They're welcomed as an important part of nature's balance and they add exciting variety to our world. >> [music]