Wahlberg's eagle (''Hieraaetus wahlbergi'') is a

bird of prey Birds of prey or predatory birds, also known as raptors, are hypercarnivorous bird species that actively hunt and feed on other vertebrates (mainly mammals, reptiles and other smaller birds). In addition to speed and strength, these predators h ...

that is native to

sub-Saharan Africa Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sov ...

, where it is a seasonal migrant in the woodlands and savannas. It is named after the Swedish naturalist

Johan August Wahlberg Johan August Wahlberg (9 October 1810, in Lackarebäck, Sweden – 6 March 1856, in Lake Ngami, Bechuanaland) was a Swedish naturalist and explorer. Wahlberg started studying chemistry at the University of Uppsala in 1829, and later forestry, a ...

. Like all

eagle Eagle is the common name for many large birds of prey of the family Accipitridae. Eagles belong to several groups of genera, some of which are closely related. Most of the 68 species of eagle are from Eurasia and Africa. Outside this area, just ...

s, it belongs to the family

Accipitridae The Accipitridae is one of the three families within the order Accipitriformes, and is a family of small to large birds with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects to medium-s ...

Description

It is cross-shaped in flight with straight-edged wings and a square tail. Wahlberg's eagle is a medium-sized raptor, and the sexes are similar. It is about in length with a wingspan of and a body mass of for males and for females on average. The head has a small crest, and the legs are yellow. The plumage tone is variable but may be dark brown except for dark-streaked grey undersides to the flight feathers, and a barred grey undertail. Light and dark plumage phases occur. A pale variant may be much lighter brown with whitish, rather than grey undertail and flight feather undersides. The pale variant is much less common than the darker variant.

Distribution and habitat

Wahlberg's eagle is distributed from central Chad to the north-east coast of South Africa. Its western boundary is thought to be Cameroon, although it most commonly occurs further east across the continent. Within this large range, it usually remains between sea-level and , but has also been documented at an altitude of in

Ethiopia Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the ...

. Wahlberg's eagles cover large distances in short periods. In 1994, a female Wahlberg's eagle was tracked over a period of 9 months, during which it covered over from northern Namibia to Chad and back; its range between breeding in the south and non-breeding areas in the north was , and it travelled over due north in just five days after leaving its breeding grounds.

Behaviour and ecology

Wahlberg's eagle mainly hunts

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

s (including other raptors such as the

Gabar goshawk The gabar goshawk (''Micronisus gabar'') is a small species of African and Arabian bird of prey in the family Accipitridae. Description The gabar goshawk is polymorphic and occurs in two distinct forms which fluctuate in relative abundance acro ...

and

Barn owl The barn owl (''Tyto alba'') is the most widely distributed species of owl in the world and one of the most widespread of all species of birds, being found almost everywhere except for the polar and desert regions, Asia north of the Himalaya ...

), although it also feeds on

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...

s (various lizards and snakes) and a few small

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s (

Tree squirrel Tree squirrels are the members of the squirrel Family (biology), family (Sciuridae) commonly just referred to as "squirrels." They include more than 100 arboreal species native to all continents except Antarctica and Oceania. They do not form a ...

Mongooses A mongoose is a small terrestrial carnivorous mammal belonging to the family Herpestidae. This family is currently split into two subfamilies, the Herpestinae and the Mungotinae. The Herpestinae comprises 23 living species that are native to ...

, Hares). It has also been recorded eating various

Invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s such as termites, grasshoppers and beetles. Wahlberg's eagle breeds mainly in southern Africa during the winter months. It builds a stick nest in the fork of a tree or the crown of a palm tree. Wahlberg's eagles are monogamous and form long-term pair bonds. They are well known for complex and spectacular aerial courtship displays. They are very territorial and solitary nesters. The nest is often reused by the same pair through multiple years. Their breeding season occurs during the wet season of northern South Africa from October to February as food is more readily available. The female feeds the chicks with food provided by the male eagle. Reductions in reproductive output were observed in the 1990s, which were thought to be related to increased population density in Wahlberg's eagles; breeding success was highly density dependant, and resource availability did not play a part in this phenomenon.

Taxonomy

Studies of marker gene sequences (published 2004–2005) found Wahlberg's eagle belonged to a clade containing ''Hieraaetus pennatus'', ''H. morphnoides'', ''H. ayeresii'', and ''H. (m.) weiskei''. Since then, many taxonomic checklists changed from ''Aquila wahlbergi'' to ''Hieraaetus wahlbergi''. However, the African Bird Club (as of the 2012 checklist) and the Second Southern African Bird Atlas Project (as of 2014) continue to keep ''Aquila wahlbergi'' separate from the ''Hieraaetus'' species.

References

* ''Birds of The Gambia'' by Barlow, Wacher and Disley,

External links

* Wahlberg's eagle
Species text in The Atlas of Southern African Birds
{{Taxonbar, from=Q609369

Wahlberg's eagle Wahlberg's eagle (''Hieraaetus wahlbergi'') is a bird of prey that is native to sub-Saharan Africa, where it is a seasonal migrant in the woodlands and savannas. It is named after the Swedish naturalist Johan August Wahlberg. Like all eagles, it ...

Birds of prey of Sub-Saharan Africa

Birds of East Africa