Secretary Bird: Sagittariidae
Secretary Bird: Sagittariidae
SECRETARY BIRD: Sagittariidae
A secretary bird's long legs resemble those of a stork, yet it has the head and body of a bird of prey. Some people call it a "marching eagle," even though it is not an eagle. It is the only bird in its family, because there are no other birds similar enough to it. It is 4 feet (1.2 meters) tall, making it the tallest bird of prey. It has strong, thick claws that are used to kill prey and a hooked, pale gray beak. The large areas of bare skin on its face are orange.
A secretary bird's head, neck, and body feathers are mostly light gray or white. It does, however, have a crest of droopy black feathers that it can raise when it is excited. The bird has black flight feathers and black feathers covering the top half of its legs. The bird's tail feathers are black and white and the two middle tail feathers are twice as long as the others.
The male and female secretary birds look alike. The sizes of the birds in a pair may vary, the male being bigger at times, the female bigger at other times. The length from their beaks to the end of their long tails ranges from 49 to 59 inches (1.2 to 1.5 meters). They weigh between 7.5 and 9.5 pounds (3.4 and 4.3 kilograms).
They live south of the Sahara Desert in Africa, except for the heavily wooded areas in western Africa.
Secretary birds live wherever there are plenty of prey animals available in a variety of grasslands and farmlands. They may enter deserts after a heavy rain, and they sometimes go to clearings in forests. They roost and nest in low trees growing in the grasslands. They cannot live in heavy forests, because it is difficult for them to fly among the trees.
Secretary birds usually do not fly as they hunt for prey. They often walk along in the tall grass, trying to frighten little animals out of hiding, to then stomp or kick the animals to death. The creatures they kill this way can be moths, grasshoppers, other large insects, and mammals as small as mice or as big as hares and mongooses. Lizards and game birds are also a part of their diet. When they find small insects and eggs, they snatch them with their beaks. The exact diet of secretary birds depends on where they live; locusts and rodents are mostly found in one region, while beetles and lizards are plentiful in another area. When secretary birds see flames, they run toward the fire. They do this because they know that hundreds of small prey animals flee for their lives ahead of the fires, creating a source of food. If the fire comes too close, the secretary birds can always fly off.
Secretary birds stoop to pick up their prey only after it has stopped moving, and when they can, they swallow it whole. Once in a while, they tear the biggest prey to pieces and store it under a bush to eat it later.
Depending on which book or website you read, you will find different origins of the secretary bird's strange name. Some say the bird got its name from its crest, which looks like the quill pens that old-time secretaries kept handy in their hair. The secretaries could pull out a quill whenever it was time to write something. Another theory is that the name comes from the Arabic words saqu ettair, meaning hunter bird. Others say the bird was named for its croak, which sounds a little something like its name.
Secretary birds are most famous for their ability to kill snakes, even poisonous ones, although snakes are only a small part of their diet. Their long legs are covered with scales that protect them from snakebites. The birds can also shield themselves from bites with their wing feathers. Sometimes they run quickly after snakes to catch them. They kill snakes the same way they kill other animals, by pouncing on them and kicking them, then striking the back of the snake's head with a talon for the killing blow. When swallowed whole, snakes usually take a longer time to go down than most prey, because the birds slowly suck them in.
Because secretary birds swallow most of their prey whole, they have to get rid of the bones, fur, feathers, and scales that they cannot digest. They regurgitate (cough up) these unwanted parts in large pellets. The sausage-shaped pellets can be as long as 4 inches (10 centimeters).
BEHAVIOR AND REPRODUCTION
Secretary birds can fly well, but they usually prefer to run unless they need to fly to escape danger. When they are looking for a mate, they also do some high-flying acrobatics as part of their courtship displays. They fly high, dive down, and swoop up again. They also dash along the ground with their wings held above their backs, zig-zagging through the tall grass while making croaking noises.
Once secretary birds have found a mate, they usually stay together for life. They defend a large territory where they hunt for food. These territories are between 7.7 to 193 square miles (20 to 500 square kilometers), depending on how plentiful the food is. Male and female secretary birds usually stay within sight of each other on their territory. Sometimes they hunt alone, but then they call to each other to keep in touch. When they are done hunting in an area, they may rest or ride high in the sky on thermals (rising bubbles of warm air). They soar on broad wings to their nest, to water, or to other hunting areas. If they discover other secretary birds in their territory, they chase and kick the other birds, making loud, croaking noises. At sunset, they usually return to their roost site. Unlike most birds, secretary birds sleep in their nests year round, not just when they raise their young. The nest is big enough for both of them to lie down in at night, and they may use the same nest and add to it year after year.
Before secretary birds build a nest, the pair finds a tree or bush with a flat top. They prefer acacia (uh-KAY-shah) trees for their nest. They stomp around on top of the tree or bush until it is flat. Then they bring twigs and sticks to make a platform as big as 6.6 feet (2 meters) in diameter. They line it with a bed of dry grass to make a soft place for the eggs and chicks. When the time is right to raise a family, the female lays between one and three eggs. The parents take turns sitting on the eggs, which hatch in forty-two to forty-six days. At first, the parents dribble partially digested food and some water into their chicks' beaks, and then tear up the food that they feed the chicks. Soon, the chicks can handle larger prey because they have big heads for their size. At just a few weeks of age, they can open their mouths so wide that they can gulp down snakes and other prey whole. The legs of young secretary birds grow so fast that the scales keep popping off and being replaced by new scales. They are not able to stand until they are ready to fly, which can be anywhere from 65 to 106 days. Their rate of growth depends on how much food their parents are able to catch for them.
Secretary birds usually breed during the summer rains, because plenty of food is available. They can nest at any time of the year, but it is also dependent on food availability. In fact, they may raise three sets of chicks in one year and none in the next, depending on the supply of prey. Pairs of secretary birds will move away from their territories and find a new place to live if food continues to be scarce.
SECRETARY BIRDS AND PEOPLE
Scientists study the pellets of secretary birds. The bones and feathers in the pellets give them an easy way to find out what the birds have been eating. The birds are valuable to farmers because they eat insects and rodents that might otherwise eat grain. Bird watchers in Africa enjoy seeing these long-legged raptors that are famous for killing snakes.
Secretary birds are not threatened, and they are protected by laws in most African countries, although some people hunt them illegally.
FOR MORE INFORMATION
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Burton, Maurice and Robert Burton. International Wildlife Encyclopedia, 3rd ed. Vol. 17. Tarrytown, NY: Marshall Cavendish Corporation, 2002.
Burton, Philip, and Trevor Boyer. Birds of Prey. New York: Gallery Books, 1989.
Parry-Jones, Jemima. Eyewitness: Eagle & Birds of Prey. London and New York: Dorling Kindersley, 2000.
Petty, Kate. Birds of Prey. New York: Gloucester Press, 1987.
Reid, Struan. Bird World. Brookfield, CN: The Millbrook Press, 1991.
Stuart, Chris and Tilde. Birds of Africa, From Seabirds to Seed-Eaters. Cambridge, MA: The MIT Press, 1999.
van Perlo, Ber. Birds of Southern Africa. Princeton, NJ: Princeton University Press, 2001.
Weidensaul, Scott. The Raptor Almanac. New York: The Lyons Press, 2000.
"Birds of Africa (The Secretary Bird)." Scienceland (Spring 1997): 24–25.
Holtzen, Ellen. "The Fire Bird." Ranger Rick (November 1984): 46–47.
Kemp, M. I., and A. C. Kemp. "Bucorvus and Sagittarius: Two Modes of Terrestrial Predation." Proceedings Symposium on African Predatory Birds, ed. Alan Kemp. Northern Transvaal Ornithological Society, Pretoria. (1977).
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"Secretary Bird." Kenya Birds. http://www.kenyabirds.org.uk/secretary.htm (accessed May 17, 2004).
Raptor Conservation Group, Endangered Wildlife Trust. http://www.ewt.org.za