Sagittariidae

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, hawks, vultures, and harriers, it is given its own family, Sagittariidae. It appears on the coats of arms of Sudan and South Africa. In 1769, Arnout Vosmaer was the first European to describe the secretarybird in one of the pamphlets later collected as his Regnum Animale, naming it Sagittarius for its gait which was thought to resemble an archer's. He also mentioned that it was known as the Secretarius by farmers at the Cape of Good Hope who had domesticated it to combat pests around homesteads. In 1779 English illustrator John Frederick Miller also described it as secretarybird, and it was soon after assigned to its own genus Sagittarius by French naturalist Johann Hermann in his Tabula Affinitatum 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 than Accipitridae 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 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 but France. 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 secretary bird. Though strongly convergent with the modern secretarybird, the extinct raptor Apatosagittarius is thought to be an accipitrid. 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 their 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 secretary bird's 'quills' to a quiver of arrows, and the specific epithet serpentarius recalls the bird's skill as a hunter of reptiles. The secretary bird is instantly recognizable as a very large bird with an eagle-like body on crane-like legs which increases the bird’s height to as much as 1.3 m (4.3 ft) tall. This bird has an eagle-like head with a hooked bill, but has rounded wings. Height can range from 90 to 137 cm (35 to 54 in). Total length from 112 to 152 cm (44 to 60 in) and the wingspan is 191–220 cm (75–87 in). Body mass can range from 2.3 to 5 kg (5.1 to 11.0 lb) with 20 birds from southern Africa found to weigh an average of 4.02 kg (8.9 lb). Other attempts to estimate the mean weight range for secretary birds correspondingly lie between 3.5 and 4.2 kg (7.7 and 9.3 lb). The tarsus of the secretary bird averages 31 cm (12 in) and the tail is 57–85 cm (22–33 in), both factor into making them both taller and longer than any other species of raptor since these features are not as long in any other living 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. Secretary bird flight feathers and thighs are black, while most of the coverts are grey with some being white. It has a large wedge-shaped tail with alternating white and black banding at its ends. 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-orange face as opposed to the yellow facial skin of the young.