Secretary bird
The secretarybird (Sagittarius serpentarius) is a large, mostly terrestrial bird of prey found only in Africa. John Frederick Miller described the species in 1779. Although a member of the order Accipitriformes, which also includes many other diurnal birds of prey such as kites, hawks, vultures, and harriers, the secretarybird is placed in its own family, Sagittariidae.
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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CarnivoreA carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of a...
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InsectivoresAn insectivore is a carnivorous plant or animal that eats insects. An alternative term is entomophage, which also refers to the human practice of e...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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ArborealArboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some anima...
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Pursuit predatorPursuit predation is a form of predation in which predators actively give chase to their prey, either solitarily or as a group. Pursuit predators r...
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AltricialAltricial animals are those species whose newly hatched or born young are relatively immobile. They lack hair or down, are not able to obtain food ...
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NomadicNomadic animals regularly move to and from the same areas within a well-defined range. Most animals travel in groups in search of better territorie...
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TerritorialA territory is a sociographical area that which an animal consistently defends against the conspecific competition (or, occasionally, against anima...
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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CursorialA cursorial organism is one that is adapted specifically to run. An animal can be considered cursorial if it has the ability to run fast (e.g. chee...
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MonogamyMonogamy is a form of relationship in which both the male and the female has only one partner. This pair may cohabitate in an area or territory for...
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Generally solitaryGenerally solitary animals are those animals that spend their time separately but will gather at foraging areas or sleep in the same location or sh...
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Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withThe secretarybird is instantly recognizable as a very large terrestrial bird with an eagle-like head and body on crane-like legs. The neck is not especially long, and can only be lowered down to the intertarsal joint, so birds must stoop to reach down to the ground. During the flight, two elongated central feathers of the tail extend beyond the feet, and the neck stretches out like a stork. The plumage of the crown, upperparts, and lesser and median wing coverts is blue-grey, and the underparts and underwing coverts are lighter grey to grey-white. The crest is made up of long black feathers arising from the nape. The scapulars, primary and secondary flight feathers, rump, and thighs are black, while the uppertail coverts are white, though barred with black in some individuals. The tail is wedge-shaped with white tipping, marbled grey, and black coloring at the base, and two broad black bands, one at the base and the other at the end. Sexes resemble one another, although the male tends to have longer tail feathers, more head plumes, a shorter head, and more blue-grey plumage. Adults have a featherless red-orange face with pale brown irises and a yellow cere. The legs and feet are pinkish-grey, and the upper legs are clad in black feathers. The toes are short and stout so the bird is unable to grasp objects with its feet. The rear toe is small and the three forward-facing toes are connected at the base by a small web. Immature birds have yellow rather than orange bare skin on their faces, more brownish plumage, shorter tail feathers, and greyish rather than brown irises.
Secretarybirds are found in sub-Saharan Africa and are generally non-migratory, though they may be locally nomadic as they follow rainfall and the resulting abundance of prey. Their range extends from Senegal to Somalia and south to Cape Province, South Africa. Secretarybirds prefer open grasslands, savannas, and shrubland (Karoo) rather than forests and dense shrubbery which may impede their cursorial existence. They can be found at a variety of elevations, from the coastal plains to the highlands. They also occur in agricultural areas and avoid deserts.
Secretarybirds are not generally gregarious aside from pairs and their offspring. They roost in trees and set off 1-2 hours after dawn, generally after spending some time preening. Mated pairs roost together but may forage separately, though often remaining in sight of one another. After spending much of the day on the ground, secretarybirds return at dusk. Unlike most birds of prey, these birds hunt their prey on foot. Adults hunt in pairs and sometimes as loose family flocks, stalking through the habitat with long strides. The birds often flush out prey from tall grass by stomping on the surrounding vegetation. Their crest feathers may raise during a hunt, which may serve to help scare the target and provide shade for the face. A bird will chase after prey with the wings spread and kill by striking with swift blows of the feet. Only with small prey items such as wasps will the bird use its bill to pick them directly. Occasionally, like other raptors, they will hold down a food item with their feet while tearing it apart with their bill. Secretarybirds are normally silent but can utter a deep guttural croaking noise in nuptial displays or at nests. They make this sound when greeting their mates or in a threat display or fight against other birds, sometimes throwing their head backward at the same time. When alarmed, secretarybirds may emit a high-pitched croak. Mated pairs at the nest make soft clucking or whistling calls. Chicks make a sharp sound heard as 'chee-uk-chee-uk-chee-uk' for their first 30 days.
Secretarybirds are carnivores. Their diet consists of insects such as locusts and beetles, mammals ranging in size from mice to hares and mongoose, crabs, lizards, snakes, tortoises, small birds, bird eggs, and sometimes dead animals killed in grass or bushfires.
Secretarybirds form monogamous pairs that last for life. They are territorial and defend a large area of around 50 km2 (19 sq mi). They can breed at any time of the year, more frequently in the late dry season. During courtship, they exhibit a nuptial display by soaring high with undulating flight patterns and calling with guttural croaking. Males and females can also perform a grounded display by chasing each other with their wings up and back, which is also the way they defend their territory. The nest is built by both sexes at the top of a dense thorny tree, often an Acacia, at a height of between 2.5 and 13 m (8 and 40 ft) above the ground. The nest is constructed as a relatively flat platform of sticks lined with grass and the occasional piece of dung. The female lays the clutch of 1-3 elongated chalky bluish-green or white eggs. Both parents incubate the eggs that hatch after around 45 days and feed the young. The adults regurgitate food onto the floor of the nest and then pick up items and pass them to the chicks. For the first 2 or 3 weeks after the eggs hatch the parents take turns to stay at the nest with the chicks. The young can stand up and feed after 40 days, although the parents still feed them after that time. At 60 days, the chicks start to flap their wings and typically leave the nest between 75 and 80 days of age. They will disperse from their natal range between 4 and 7 months old.
Although widespread, the secretarybird is thinly distributed across its range. Its population is mainly threatened by loss of habitat due to fragmentation by roads and development and overgrazing of grasslands by livestock. This species also suffers from hunting, persecution, disturbance by humans, and poisoning.
According to the IUCN Red List, the total population size of the secretarybird is around 6,700-67,000 mature individuals. Currently, this species is classified as Vulnerable (VU) on the IUCN Red List, and its numbers today are decreasing.
