Booted Eagle

Identification

The booted eagle is a small eagle, comparable to the common buzzard in size though more eagle-like in shape. Males grow to about 510–770 g (1.12–1.70 lb) in weight, with females about 840–1,025 g (1.852–2.260 lb) with a length of 40 cm and a wingspan of 110–132 cm. There are two relatively distinct plumage forms. Pale birds are mainly light grey with a darker head and flight feathers. The other form has mid-brown plumage with dark grey flight feathers. It was found in a study investigating polymorphism that these discrete colour morphs follow a Mendelian inheritance pattern, where the paler allele is dominant. In South Africa, 20% of the population is the dark colour morph. Booted eagles are typically seen in pairs or as solitary individuals. However, the study found that the darker morphs are much more common in the eastern populations such as in Russia.The call is a shrill kli-kli-kli.

Taxonomy

The booted eagle was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the eagle, falcons and relatives in the genus Falco and coined the binomial name Falco pennatus. Gmelin based his description on "Le Faucon Patu" or "Falco pedibus pennatis" that had been described and illustrated in 1760 by the French zoologist Mathurin Jacques Brisson. Brisson had examined a specimen in the collection of Madame de Bandeville who was also known as Marie Anne Catherine Bigot de Graveron (1709-1787). The booted eagle is now placed in the genus Hieraaetus that was introduced in 1844 by the German naturalist Johann Jakob Kaup. The genus name combines the Ancient Greek hierax meaning "hawk" with aetos meaning "eagle". The specific epithet pennatus is Latin and means "feathered". The booted eagle has no recognised subspecies.<p>Based on recent genetic research some authors reclassified this species to the genus Aquila, along with some or all other Hieraaetus species. As it is the type species of Hieraaetus, should any of the hawk-eagles have been retained in a distinct genus then a new name for that group would have been necessary. However, DNA research has shown it forms a monophyletic clade with Ayres's hawk eagle, Wahlberg's eagle, little eagle and the pygmy eagle and this clade is often treated as forming the genus Hieraeetus and most reference lists currently use H. pennata.<p>Although some authors name a number of subspecies most now treat it as a monotypic species.<p>Aquila minut described by Brehm (1831) is this bird. The fossil bird described under the same name by Milne-Edwards (1871) is preliminarily known as Hieraaetus edwardsi, but might belong in Aquila.

Scientific name

Hieraaetus pennatus

Authority

(Gmelin, JF, 1788)

Order

Accipitriformes

Family

Accipitridae

Genus

Hieraaetus

Range and habitat

The booted eagle has breeding populations in many different regions in both the northern and southern hemisphere. These include southern Europe, North Africa and across Asia, and also in western South Africa and Namibia.The northern populations are migratory spending November to February in Sub-Saharan Africa and South Asia, while the small southern African populations is sedentary. This is a species of wooded, often hilly countryside with some open areas. It breeds in rocky, broken terrain but migrants will use almost any type of habitat other than dense forest. The birds of the Palearctic breeding population tend to nest in coniferous or deciduous woodlands and often in trees.<p>It is believed that there may be three separate groups of booted eagles in Southern Africa. There is evidence of a population which breeds in the south-western Cape region of South Africa, arriving in early August, laying eggs in September, and leaving in March of the following year. From about April to July the birds migrate northwards, some possibly overwintering in Namibia. A small breeding population in Northern Namibia has also been observed. The third group is a non-breeding population thought to migrate south from Eurasia and North Africa in summer, however no empirical evidence of this has been documented. These booted eagle populations are not sub-specifically distinct from those in Palearctic regions.<p>In South Africa, booted eagles also occur in hilly and open landscapes and in contrast to their Northern Hemisphere conspecifics, typically breed strictly on rocky cliffs in ravines and gorges. However, evidence has been found in South Africa of birds nesting in trees such as Euphorbias. This bird is most common in the low stature shrublands of the Fynbos and Karoo, and more specifically the ecotone between the two biomes.

Breeding range

PAL : sw Europe and nw Africa to c Asia and n India; also South Africa

Non-breeding range

AF, s Asia

Migration

Complete migrants

Behavior

Migration pattern: Complete migrants.

Conservation

Population trend: stable.

Population trend

stable