Bateleur

Bateleur
Scientific classification
Kingdom Information
Domain	Eukaryota
Kingdom	Animalia
Subkingdom	Bilateria
Branch	Deuterostomia
Phylum Information
Phylum	Chordata
Sub-phylum	Vertebrata
Infraphylum	Gnathostomata
Class Information
Superclass	Tetrapoda
Class	Aves
Sub-class	Neornithes
Infra-class	Neoaves
Order Information
Order	Accipitriformes
Sub-order	Accipitres
Family Information
Superfamily	Accipitroidea
Family	Accipitridae
Sub-family	Circaetinae
Genus Information
Genus	Terathopius
Species Information
Species	T. ecaudatus
Population statistics
Population	10,000-100,000 (2016 est.)
Conservation status	Near Threatened

The bateleur (Terathopius ecaudatus) is a species of eagle of the family Accipitridae, and found over much of sub-Saharan Africa. It is known for the tumbling aerial displays which gives it its name.

Description

Bateleurs are up to 30 inches long with a wingspan of nearly 6 feet. Males have a black head, neck, and chest, a chestnut or reddish-brown back and tail, and gray shoulders. The bare face is a brilliant-red, and the short legs and talons are reddish-orange. Females are similar, with gray-colored secondaries instead of black.

Habitat

The bateleur inhabits open and semi-open landscapes such as grasslands, dry and thornscrub savannahs, to light dry forest, from sea level to approximately 13,000 feet elevation. It is not found in denser forests and wetlands, but due to the long flights it makes throughout its range it may be seen over these areas.

Diet

The food prey of the bateleur is very diverse. It will make an active hunt for mammals and birds - both account for up to 90% of prey taken - as well as specific searches for carrion and dead fish, bird eggs, crabs, and insects such as termites or grasshoppers. In contrast to other snake eagles, the proportion of reptiles taken is quite low. In places with a rich food supply (such as fire or flooded areas, as well as termite mounds) bateleurs can gather in flocks of 50 or more. Juvenile or subadult birds are more common on larger carcasses than adult individuals.

The bateleur can spend up to eight or nine hours a day on flights in search of food, covering an area of ​​21 to 55 square miles, and searching the landscape from a height of about 170 feet.

Reproduction

The breeding season varies with location: in West Africa it's between September and May; it is throughout the year in East Africa; and it's from December to August in southern Africa. The courtship dance - as well as the reason for the bird's name - is aerial, involving extensive rocking, rollovers and dive-like maneuvers, a reminder to the naturalists who described it of the acrobats and jugglers on the streets of France.

The nest, which is up to 4 feet wide and 3 feet high, is constructed from branches and placed in the uppermost branches of large trees, such as acacia or baobabs. Occasionally they take over the nests of other bird species, and often near rivers. It is reused over several years and increases in size over time. Usually, however, a new nest is built every three years.

The clutch consists of a single, dirty white egg, incubated between 52 and 59 days by both parents. The nestling time varies greatly, it can be between 93 and 194 days, but usually lasts between 110 and 112 days. The young birds are dependent on their parents for up to four months after they have fledged. Both parents participate in the rearing of the young and are supported by other adult birds or subadult birds. Up to a third of the clutches fail during the nesting season, due to predators taking advantage of an unguarded nest during the long feeding flights of the adult birds.

Threats

The bateleur is rare, but locally it can be very common, such as at the Masai Mara. In large parts of its range the bird has been subject of relatively-large declines of up to 50% since the 1970s, the causes of which are still continuing to the point where the species is classified as "near-threatened" by the ICUN. Particularly large were the losses since the 1940s in South Africa, where the species fell by up to 80%. Originally, the Transvaal population comprised 2000-2500 breeding pairs, compared with only 420-470 pairs at the beginning of the 1980s. However, this number rose again to about 600 couples in the 1990s.

The world population is probably between 10,000 and 100,000 individuals. The numbers are declining in Ivory Coast, Nigeria, Sudan and Somalia, parts of Kenya, Tanzania and Zimbabwe, as well as in Namibia, Botswana and parts of South Africa. In contrast, there were increases in Masai Mara, northern South Africa and possibly Uganda. No evidence has been available from southwestern Arabia since 1999.

The main threat in many places is the direct persecution by commercial large-scale farmers - and sometimes smaller, arable farming tribal societies - who leave in the fields poisoned carcasses, under the belief that this and other raptors are responsible for killing livestock. Other causes are the increasing burden of pesticides, the destruction of habitat, disruption by the expansion of human settlements and the catch for international trade.