Aztec Thrush
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The Aztec thrush (''Ridgwayia pinicola'') is a species of
bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
in the family
Turdidae The thrushes are a passerine bird family, Turdidae, with a worldwide distribution. The family was once much larger before biologists reclassified the former subfamily Saxicolinae, which includes the chats and European robins, as Old World flyca ...
. It is found mainly in
Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
, but
vagrants Vagrancy is the condition of wandering homelessness without regular employment or income. Vagrants usually live in poverty and support themselves by travelling while engaging in begging, scavenging, or petty theft. In Western countries, ...
are occasionally seen in the
United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
. Its natural
habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...
is
montane forest Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures lapse rate, fall as elevation increases, causing the ecosystem to stratify. This stratification is ...
s. The IUCN Red List denotes it as a least-concern species.


Taxonomy

Philip Sclater Philip Lutley Sclater (4 November 1829 – 27 June 1913) was an England, English lawyer and zoologist. In zoology, he was an expert ornithologist, and identified the main zoogeographic regions of the world. He was Secretary of the Zoological ...
described the species as ''Turdus pinicola'' from southern Mexico in 1859. In 1882,
Leonhard Stejneger Leonhard Hess Stejneger (30 October 1851 – 28 February 1943) was a Norwegian-born American ornithologist, herpetologist and zoologist. Stejneger specialized in vertebrate natural history studies. He gained his greatest reputation with repti ...
moved the species into its own genus, ''Ridgwayia''. The genus name honors ornithologist
Robert Ridgway Robert Ridgway (July 2, 1850 – March 25, 1929) was an American ornithologist specializing in systematics. He was appointed in 1880 by Spencer Fullerton Baird, secretary of the Smithsonian Institution, to be the first full-time curator of birds ...
. It is also placed in the genus '' Zoothera''. Two subspecies are recognized: ''R. p. maternalis'' found in the southwestern United States and northwestern Mexico, and ''R. p. pinicola'' in southwestern Mexico.


Description

The Aztec thrush is long and weighs . The adult male has a dark brown hood, the head, neck and upper mantle being dark brown, with pale flecks or streaks. There may be a pale brown
supercilium The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head.Dunn and Alderfer (2006), p. 10 Also k ...
. The back, scapulars, median
coverts A covert feather or tectrix on a bird is one of a set of feathers, called coverts (or ''tectrices''), which cover other feathers. The coverts help to smooth airflow over the wings and tail. Ear coverts The ear coverts are small feathers behind t ...
and greater coverts are dark brown, the greater coverts having white edges. The primary coverts are black, with grey tips. The
flight feather Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tai ...
s are black, with some white patches. The lesser and median coverts of the underwing are white, and the greater coverts are blackish grey. The tail is black or blackish brown, with whitish grey tips. The breast is dark brown, and the rest of the underparts is white. The beak is dark brown, and the legs are pale pink. The female does not have a hood, is paler, and has larger streaks. The juvenile bird is blackish, with golden-buff marks on its head and back. It has a cinnamon or reddish-brown lower back, a black tail and scaled underparts.


Distribution and habitat

The species is found in Mexico, in mountains above sea level. Its habitat is mostly ravines of pine and pine-oak forests. The Aztec thrush is a vagrant in western Texas to southeastern Arizona. The first record in the United States was an immature bird observed in 1977 in
Big Bend National Park Big Bend National Park is a List of national parks of the United States, national park of the United States located in West Texas, bordering Mexico. The park has national significance as the largest protected area of Chihuahuan Desert topograph ...
, Texas.


Behaviour

This bird usually associates in small groups, sometimes joining
mixed-species foraging flock A mixed-species feeding flock, also termed a mixed-species foraging flock, mixed hunting party or informally bird wave, is a flock (birds), flock of usually insectivorous birds of different species that join each other and move together while fora ...
s. It forages in dense vegetation on the ground and eats berries and insects. It has been observed cocking its head while feeding. Its calls include , and its song is the call repeated and mixed with some other sounds. In the southern part of its range, breeding takes place from May to June. The nest is cup-shaped and made of grass and moss. The eggs are pale blue.


Status

The ''R. pinicola'' population is estimated to be less than 50,000 individuals. The population trend is probably declining because of habitat loss. The decline does not appear rapid enough to meet the criteria for vulnerable status, and the range size and population size are both above the threshold for vulnerable status, so the
IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...
has assessed the species to be of
least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...
.


References

{{Taxonbar, from=Q568863 Aztec thrush Endemic birds of Mexico Aztec thrush Aztec thrush Taxonomy articles created by Polbot Birds of the Sierra Madre Occidental Birds of the Sierra Madre del Sur