Secretary Bird: Sagittariidae
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.