Red-backed Buzzard
| Red-backed Buzzard | ||||||||||
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Red-backed buzzard, female |
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| Geranoaetus polyosoma | ||||||||||
| ( Quoy & Gaimard , 1824) |
The red-backed buzzard ( Geranoaetus polyosoma , syn .: Buteo polyosoma ) is a species from the hawk-like family. Its distribution area is the west and south of South America. Two subspecies are described.
Appearance
The red-backed buzzard reaches a body length of 46 to 56 centimeters. The wing length is 35 to 45 and the wingspan is 110 to 120 centimeters. Red-backed buzzards weigh an average of 950 grams. The females are on average six percent larger and heavier than the males. Females usually have a reddish brown coat, but there are a few males who also have this.
The plumage color varies greatly from person to person and a total of three color morphs are distinguished. The light colored morph has a white underside of the body with flanks that are pale brown. The skull, the neck and the wing covers are dark brown, the wings are slate brown. The males of this morph are usually slate gray on the upper side and whitish on the lower side. The dark morph has a red-brown underside of the body and a slate-brown upper side or is colored slate-gray throughout. In the sparred morph, the females have a gray-black head, the under-tail-cover and the flanks are slate-gray or reddish-brown or they are black-gray on the upper side of the body with a variable proportion of reddish-brown feathers.
The beak of all color morphs is black-gray with a black beak tip, the legs and feet are bright yellow with black claws. The eyes are either yellowish or brownish. Not yet sexually mature birds are usually dark brown on the upper side of the body with a variable proportion of reddish brown on the coat, the gray tail is black striated. There are whitish spots on the neck.
Distribution area
The distribution area of the red-backed buzzard extends from Colombia via Ecuador and Peru to the south of Bolivia and Chile and in Argentina to Tierra del Fuego . The red-backed buzzard is also one of the breeding birds in the Falkland Islands . It is particularly widespread in southern South America, where it occurs 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 an endemic species of the island Alejandro Selkirk , the westernmost and second largest of the Pacific Ocean lying Juan Fernández Islands .
Way of life
The red-backed buzzard eats small mammals such as hares, rats, mice, and rabbits, as well as birds such as geese and waders. The food spectrum also includes carrion and domestic fowl.
Red-backed buzzards usually build their nests on ledges. They usually use their eyrie again every year. At the beginning of the breeding season, further twigs and twigs are built into the eyrie so that clumps can become very large over the years. The clutch consists of two to three almost elliptical eggs. These have a white skin color and are sprinkled with reddish brown. The breeding season is 26 to 27 days and the young fledglings after forty to fifty days.
A number of more unusual nesting sites are also known of the red-backed buzzard. In the Falkland Islands, there is evidence of a breeding pair building the eyrie on discarded rolls of barbed wire. In another case, the eyrie was built on a fence post. At the airfield on Mount Pleasant, a couple nested on the mast of a radar station. Since the breeding pair aggressively defended the immediate nesting area so that maintenance of the radar systems was no longer possible, a new mast was erected nearby and the nest was relocated there. The breeding pair successfully incubated at this point in the next reproductive period.
supporting documents
literature
- Hadoram Shirihai: A Complete Guide to Antarctic Wildlife - The Birds and Marine Mammals of the Antarctic Continent and Southern Ocean , Alula Press, Degerby 2002, ISBN 951-98947-0-5
- Robin and Anne Woods: Atlas of Breeding Birds of the Falkland Islands , Anthony Nelson, Shorpshire 1997, ISBN 0904614-60-3
Single receipts
Web links
- Geranoaetus polyosoma inthe IUCN Red List of Threatened Species 2013.1. Listed by: BirdLife International, 2012. Retrieved November 18, 2013.