About Cyanoliseus patagonus (Vieillot, 1818)
Adult burrowing parrots (Cyanoliseus patagonus) measure 39–52 cm in total length, with a 23–25 cm wingspan and a long, graduated tail that ranges 21 to 26 cm. The species is slightly sexually dimorphic in size: males are slightly larger, weighing approximately 253–340 g, while females weigh 227–304 g. It is the largest member of the New World parakeet group commonly known as conures. The burrowing parrot is a distinctive species with a bare white eye ring and a white post-ocular patch. Its head and upper back are olive-brown, its throat and breast are grey-brown with a variable whitish pectoral marking that rarely extends across the entire breast. Its lower thighs and abdominal center are orange-red; researchers think the extent and hue of this red plumage indicates an individual’s quality as a breeding partner and parent. Its lower back, upper thighs, rump, vent and flanks are yellow, and its wing coverts are olive green. Its tail is olive green with a blue tint when viewed from above, and brown when viewed from below. The species has a grey bill, yellow-white iris, and pink legs. Immature birds resemble adults, but have a horn-colored patch on the upper mandible and a pale grey iris. While both sexes look very similar to the unaided human eye, the species is sexually dichromatic: males typically have significantly redder and larger abdominal red patches, and the two sexes look different under ultraviolet light: males have brighter green feathers, while females have brighter blue feathers. Burrowing parrots are found across most of Argentina, with isolated populations in central Chile. Central and southern Argentine populations are austral migrants that travel north as far as southern Uruguay in winter, while Chilean populations move vertically downslope to avoid colder high elevations. Populations in northwestern Argentina also move based on food availability. The species prefers dry, open country, especially near water courses, and occurs up to 2000 m in elevation. Its natural habitats include montane grassy shrubland, Patagonian steppes, arid lowlands, woodland savanna, and the plains of the Gran Chaco. It may also live on farmland and at the edges of urban areas. Burrowing parrots are best known for their nesting behavior: they excavate extensive burrows into limestone or sandstone cliff faces, most often in ravines. These burrows can reach up to 3 m deep into the cliff, connect with other tunnels to form a labyrinth, and end in a dedicated nesting chamber. Breeding pairs reuse burrows from previous years and may enlarge them. The species nests in large colonies, some of the largest ever recorded for parrots, a behavior thought to reduce predation. Burrowing parrots tend to select larger, taller ravines, which allow larger colonies and higher placement of burrows, resulting in higher breeding success. When suitable ravines or cliffs are not available for nesting, burrowing parrots will use human-made substrates such as quarries, wells, and pits. Rarely, they have been recorded nesting in tree cavities. Research confirms burrowing parrots are both socially and genetically monogamous. The breeding season begins in September, and eggs are laid through December, with clutch sizes ranging from two to five eggs. Incubation lasts 24–25 days; only the female incubates, while the male provides her with food. Eggs hatch asynchronously, and mortality is higher for the fourth and fifth chicks in a clutch. Both parents care for the chicks. Chicks fledge from late December to February, approximately eight weeks after hatching, and fledglings remain dependent on their parents for up to four months.
