The Secretarybird or Secretary Bird (Sagittarius serpentarius) is a very large, mostly terrestrial bird of prey. Endemic to Africa, it is usually found in the open grasslands and savannah of the sub-Saharan region. Although a member of the order Accipitriformes, which also includes many other diurnal raptors such as kites, buzzards, vultures, and harriers, it is given its own family, Sagittariidae.
It appears on the coats of arms of Sudan and South Africa.
First described by English illustrator John Frederick Miller in 1779, the Secretarybird was soon assigned to its own genus, Sagittarius, by French naturalist Johann Hermann in his Tabula Affinatum Animalium. It was not until 1935 that the species was moved to its own family, distinct from all other birds of prey—a classification confirmed by molecular systematics. Recent cladistic analysis has shown Sagittariidae to be an older branch of the diurnal birds of prey thanAccipitridae and Falconidae, but a younger divergence than Cathartidae. Sometimes, the enigmatic bird Eremopezus is classified as an early relative of the Secretarybird, though this is quite uncertain as the bird is only known from a few fragmentary body parts such as the legs. The earliest fossils associated with the family are two species from the genus Pelargopappus. The two species, from the Oligocene and Miocene respectively, were not discovered in Africa butFrance. The feet in these fossils are more like those of the Accipitridae; it is suggested that these characteristics are primitive features within the family. In spite of their age, it is not thought that the two species are ancestral to the Secretarybird.
Its common name is popularly thought to derive from the crest of long quill-like feathers, lending the bird the appearance of a secretary with quill pens tucked behind his or her ear, as was once common practice. A more recent hypothesis is that “secretary” is borrowed from a French corruption of the Arabic saqr-et-tair or “hunter-bird.”
The generic name “Sagittarius” is Latin for “archer,” perhaps likening the Secretarybird’s “quills” to a quiver of arrows, and the specific epithet “serpentarius” recalls the bird’s skill as a hunter of reptiles. Alternatively, the name could refer to the last two constellations in the Zodiac, Sagittarius and Serpentarius (now known as Ophiuchus).
The Secretarybird is instantly recognizable as having an eagle-like body on crane-like legs which increases the bird’s height to as much as 1.3 m (4 ft) tall. This bird has an eagle-like head with a hooked bill, but has rounded wings. Body weight can range from 2.3 to 4.5 kg (5.1 to 9.9 lb) and height is 90–130 cm (35–51 in). Total length from 112 to 152 cm (44 to 60 in) and the wingspan is 191–220 cm (75–87 in). The tarsus of the secretarybird averages 31 cm (12 in) and the tail is 57–85 cm (22–33 in), both of which factor into making them both taller and longer than any other species of raptor. The neck is not especially long, and can only be lowered down to the inter-tarsal joint, so birds reaching down to the ground or drinking must stoop to do so.
From a distance or in flight it resembles a crane more than a bird of prey. The tail has two elongated central feathers that extend beyond the feet during flight, as well as long flat plumage creating a posterior crest. Secretarybird flight feathers and thighs are black, while most of the coverts are grey with some being white. Sexes look similar to one another as the species exhibits very little sexual dimorphism, although the male has longer head plumes and tail feathers. Adults have a featherless red face as opposed to the yellow facial skin of the young.Secretarybirds are endemic to Sub-Saharan Africa and are non-migratory, though they may follow food sources. Their range extends from Mauritania to Somalia and south to the Cape of Good Hope. These birds are also found at a variety of elevations, from the coastal plains to the highlands. Secretarybirds prefer open grasslands and savannas rather than forests and dense shrubbery which may impede their cursorial existence. While the birds roost on the localAcacia trees at night, they spend much of the day on the ground, returning to roosting sites just before dark.