Parrocchetto delle tane

Identificazione

Adults measure 39–52 cm in length, with a wingspan of 23–25 cm and a long, graduated tail that can range from 21 to 26 cm. Burrowing parrots are slightly sexually dimorphic, with males being slightly larger and weighing approximately 253-340 g, while females weigh 227-304 g, making it the largest member of the group of New World parakeet species commonly known as conures.<p>The burrowing parrot is a distinctive parrot; it has a bare, white eye ring and post-ocular patch, its head and upper back are olive-brown, and its throat and breast are grey-brown with a whitish pectoral marking, which is variable and rarely extends across the whole breast. The lower thighs and the center of the abdomen are orange-red, and it is thought that the extent and hue of the red plumage indicates the quality of the individual as a breeding partner and parent. The lower back, upper thighs, rump, vent and flanks are yellow, and the wing coverts olive green. The tail is olive green with a blue caste when viewed from above and brown from below. The burrowing parrot has a grey bill and yellow-white iris with pink legs. Immature birds look like adults but with a horn coloured upper mandible patch and a pale grey iris.<p>While both sexes look visually similar to the human eye, the burrowing parrot is sexually dichromatic. Males tend to have significantly redder and larger abdominal red patches, and both sexes look different under UV light, with males have brighter green feathers and females having brighter blue feathers.

Tassonomia

Nome scientifico

Cyanoliseus patagonus

Autorità

(Vieillot, 1818)

Ordine

Psittaciformi

Famiglia

Psittacidae

Genere

Cyanoliseus

Areale e habitat

The burrowing parrot can be found in much of Argentina, and there are isolated populations in central Chile. In the winter, birds in central and southern Argentina may migrate north as far as southern Uruguay, making them austral migrants, while Chilean birds migrate vertically down slope to avoid colder altitudes. Movements in the populations of northwestern Argentina are also known to occur according to food availability.<p>The burrowing parrot prefers dry, open country, particularly in the vicinity of water courses, up to 2000 m in elevation. Habitats include montane grassy shrubland, Patagonian steppes, arid lowland, woodland savanna, and the plains of the Gran Chaco. They may also inhabit farmland and the edges of urban areas.

Migrazione

Complete migrants

Comportamento

The diet of the burrowing parrot comprises seeds, berries, fruits, and possibly vegetable matter, and they can be seen feeding on the ground or in trees and shrubs. Their diet varies seasonally, with fruit consumption peaking during Argentina's summer (December–February), where one study found that fruit makes up 2% of their crop contents in November–December, 74% in January, 25% in February, 35%,in March and 8% in April. Specifically, burrowing parrots have been observed feeding on the fruit from various species such as the red crowberry (Empetrum rubrum), Chilean palo verde (Geoffroea decorticans), Lycium salsum, pepper trees (Schinus sp.), Prosopis sp., Discaria sp., as well as cacti. In the winter, the burrowing parrot feeds predominantly on seeds from cultivated crops and wild plants such as thistles, as well as the Patagonian oak (Nothofagus obliqua) and the Carboncillo (Cordia decandra) in the Chilean foothills.<p>Best known for its nesting habits, the burrowing parrot excavates industrious burrows in limestone or sandstone cliff faces, often in ravines. These burrows can be as much as 3 m deep into a cliff-face, connecting with other tunnels to create a labyrinth, ending in a nesting chamber. Breeding pairs will reuse burrows from previous years but may enlarge them. They nest in large colonies, some of the largest ever recorded for parrots, which is thought to reduce predation. The parrots tend to select larger, taller ravines, allowing for larger colonies and higher burrows and resulting in higher breeding success.<p>In the absence of acceptable ravines or cliffs to use as nesting sites, burrowing parrots will use anthropogenic substrates such as quarries, wells and pits. Rarely, they have been known to nest in tree cavities.<p>Studies have shown that burrowing parrots are both socially and genetically monogamous. The breeding season begins in September, and eggs are laid up to December, with two up to five eggs laid per clutch. The incubation period is 24–25 days, where the female is the sole incubator while the male provides for her. Eggs hatch asynchronously, and mortality is higher for fourth and fifth chicks in a clutch. Both parents care for the chicks. Chicks begin to fledge in late December until February, approximately eight weeks after hatching, and the fledglings depend on their parents for up to four months.<p>In order to cope with an unpredictable climate, burrowing parrots increase their body mass and decrease their basal metabolic rate (BMR) in the winter in order to conserve energy, insulate against cold ambient temperatures and to survive reductions in food availability, in concurrence with other birds found in the southern hemisphere.

Conservazione

Tendenza della popolazione

declining