Cacatoès corella

Identification

The little corella is a small white cockatoo growing to 35–41 cm (14–16 in) in length and weighs 370–630 g (13–22 oz), with a mean weight of 525 g (1.157 lb). It is similar in appearance to both the long-billed corella and the western corella, but the little corella is smaller, and unlike either of those species, it has upper and lower mandibles of similar length. It is easily distinguished from the long-billed corella by the lack of an orange throat bar. C. s. normantoni and C. s. transfreta are a little smaller than the nominate form. C. s. normantoni is lightly brownish on the underside of flight and tail feathers. C. s. gymnopis has darker blue eye-rings, more strongly marked pink lores and a yellow wash to the lower-ear coverts. Females are slightly smaller than males in weight, wing length, culmen size, tarsus length, tail length and eye ring diameter.

Taxonomie

The first recorded description of the species was by English ornithologist John Gould in 1843. There are four subspecies as follows:<p>

Nom scientifique

Cacatua sanguinea

Autorité

Gould, 1843

Ordre

Psittaciformes

Famille

Cacatuidés

Genre

Cacatua

Répartition et habitat

The nominate form, C. s. sanguinea is found in Northern Australia. C. s. normantoni is found on the Western Cape York Peninsula. C. s. transfreta is found in New Guinea. C. s. gymnopis is found in Central, Eastern, and South-eastern Australia. Habitat ranges from the arid deserts of central Australia to the eastern coastal plains, but they are not found in thick forests. Little corellas can also be found in urban areas, including Melbourne, Canberra, Sydney and Brisbane, where they feed on lawns and playing fields. They are numerous in farmlands throughout New South Wales and Queensland, and have become so common in some areas that they are considered to be crop pests, and can be destructive to the trees in which they perch, by chewing the bark off smaller twigs.

Migration

Resident species

Comportement

Little corellas congregate in flocks of up to several thousand, which often include other birds such as galahs, sulphur-crested cockatoos and red-tailed black cockatoos. They generally roost in trees overnight, and fly off to feed in the early morning before returning in the late evening. Flocks will often fly many kilometres between their feeding and roosting areas, and in desert areas must also fly to watering holes twice a day, while corellas which live in coastal areas do not have to fly long distances to find water.[citation needed]<p>The call consists of high pitched notes and screeches somewhat similar to the sulfur-crested cockatoo. Large flocks will call simultaneously and can create a deafening screeching sound audible from several kilometers away.[citation needed]<p>Breeding occurs from May to October, and usually takes place earlier in the north of its range. The nest is usually in a tree hollow, cliff cavity or termite mound.<p>Little corellas usually feed on the ground, however occasionally feed in trees and shrubs. They eat a variety of both wild and cultivated seeds and regularly feed on lawn grasses in urban areas. They frequently feed on cereal crops such as wheat, barley and maize and can become a considerable agricultural pest in some areas.[citation needed]<p>When little corellas play, they become very noisy. They have conversations with each other, fly around and also show off. Little corellas show off by hanging themselves upside-down with their feet, beaks or both.[citation needed]

Conservation

Tendance de la population

rising