Variable Hawk
Rotrückenbussard, females
The Rotrückenbussard (Buteo polyosoma ) is a species of the family Accipitridae. Its distribution area is the western and southern South America. It describes two subspecies.
- 4.1 Literature
- 4.2 Single Documents
Features
Appearance
The Rotrückenbussard reaches a body length of 46-56 inches. The wing length is 35 to 45 and the wing span 110 to 120 centimeters. Rotrückenbussarde average weight of 950 grams. The females are around six percent on average larger and heavier than the males. Females usually have a reddish-brown coat, but there are a few males that have this also.
The plumage coloration varies individually very strong and a total of three color morphs can be distinguished. The bright color morph has white underparts with edges that are cuckoo pale brown. The top of the head, the neck and the wing-coverts are dark brown, the wings are slate brown. The males of these morphs are usually slate gray on the body top and whitish on the underparts. The dark morph has a red-brown underparts and a brown slate top, or is colored throughout slate gray. When gesperberten morph females have a gray-black head, the under tail- ceiling and the edges are slate gray or reddish brown cuckoo or they are black and gray on the body top with a variable proportion of reddish- brown feathers.
The beak is black and gray in all color morphs with a black beak, legs and feet are bright yellow with black claws. The eyes are either yellow or brown. Immature birds are on the body top is usually dark brown black striated with a variable proportion of red-brown on the mantle, the tail is gray. In the neck, there are white spots.
Distribution area
The distribution area of Rotrückenbussards extends from Colombia to Ecuador and Peru to the south of Bolivia and Chile and Argentina to Tierra Fuego of. The Rotrückenbussard also comes as breeding bird population of the Falkland Islands. It is especially prevalent in the south of South America and is there mainly in the Andean regions. During the winter months, it is also represented in Uruguay and in southeastern Brazil. The subspecies Buteo polyosoma esxul is a species endemic to the island of Alejandro Selkirk, the westernmost and second largest in the Pacific Ocean situated in the Juan Fernández Islands.
Way of life
The Rotrückenbussard eats small mammals such as rabbits, rats, mice and rabbits and birds such as geese and waders. For food spectrum sometimes including carrion and domestic poultry.
Rotrückenbussard usually build their nests on rocky ledges. Do you usually use their Horst every year. At the beginning of the breeding season, more branches and twigs are installed at the nest, so that nests over the years can be very large. The nest consists of two to three nearly elliptical eggs. These have a white shell color and are sprinkled brown. The incubation period is 26-27 days and the young birds fledge after forty to fifty days.
From Rotrückenbussard also a number of unusual nesting sites are known. A case is assigned to the Falkland Islands, where a breeding pair of the nest built on continuous cast rolls of barbed wire. In another case, the Horst was built on a fence post. At the airport, on Mount Pleasant, a pair nested on the mast of a radar station. Since the breeding pair defended the immediate vicinity Horst aggressive, so that maintenance of radar equipment was no longer possible, a new mast was erected in the vicinity and the Horst moved to there. The breeding pair hatched in the next breeding season successfully at this point.