The Clay-colored Thrush (Turdus grayi) is a common Middle American bird of the thrush family (Turdidae). It is the national bird of Costa Rica, where it is well known as the yigüirro. It was known as the Clay-colored Robin until 2010.

It ranges from South Texas (where it is rapidly expanding its range) to northern Colombia; west and north of the Isthmus of Tehuantepec. It is limited to the Atlantic slope, except for a population around Oaxaca City that probably originates from escaped cagebirds.

Description

Santo Domingo, Costa Rica

In general appearance and habits it resembles other Turdus thrushes such as the American Robin. It is about the same length or slightly smaller: 23–27 cm (9-10.5 in), and weighs 74-76 g (2.6 oz.) on average. The plumage is brownish, somewhat lighter below than above, lightest on the flanks. Birds from humid regions are darker than those from dry regions. The throat is faintly streaked. Immature birds have faint mottling on the back and underparts. The bill is greenish-yellow with a dark base, the legs are pinkish or flesh-colored, and the irises are reddish---all useful identification points.

The song, rather low-pitched and with a slow steady tempo, consists of many slurred musical phrases which are often repeated irregularly. The tock flight call is like the American Robin's but harsher.

Ecology

Juvenile bird, San José, Costa Rica

In much of its range it is familiar in yards and gardens, similar to some other thrushes such as the American Robin, the Eurasian Blackbird, and the Song Thrush. In 1977, the Costa Ricans chose the yigüirro as a national symbol (over many much more colorful birds that inhabit the country) due to its strong and melodious song that always comes during the start of the rainy season. In addition, unlike many of the forest songsters of Costa Rica, the present bird has been familiar to the general population since the country's early history, thanks to the species' tendency to live near houses and settlements.^[2]

The Clay-colored Thrush usually forages for fruit^[3] or invertebrates on the ground or near it, singly or in pairs, but flocks may feed high in fruiting trees. It will follow army ants to feed on small prey disturbed by the ant columns.

It builds a heavy cup nest of grass, moss,feathers,leaves and mud on a firm support above the ground, which may include human constructions such as windowsills. It lays 2 to 4 pale blue eggs with red-brown and gray markings between March and July and may double-brood. It is aggressive in defense of its nest having been known to mob raptors as large as Golden Eagles, but is not otherwise particularly territorial.

Footnotes

1. ^ BirdLife International (2012). "Turdus grayi". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. http://www.iucnredlist.org/apps/redlist/details/106006434. Retrieved 16 July 2012.
2. ^ Museos de Costa Rica: Simbolos Patrios: El Yigüirro [in Spanish]. Retrieved 2007-SEP-15
3. ^ E.g. of Trophis racemosa (Moraceae) and sometimes Gumbo-limbo (Bursera simaruba): Foster (2007).

3. Symbol of the city of San Pedro Sula,Cortes, Honduras...self-proclaimed "La Ciudad del Zorzal", in reference to the bird's local name "zorzal" which there abounds

References

• Foster, Mercedes S. (2007): The potential of fruiting trees to enhance converted habitats for migrating birds in southern Mexico. Bird Conservation International 17(1): 45-61. doi:10.1017/S0959270906000554 PDF fulltext
• Howell, Steven N. G. & Webb, Sophie (1995): A Guide to the Birds of Mexico and Northern Central America. Oxford University Press, Oxford & New York. ISBN 0-19-854012-4
• Sibley, David Allen (2000): The Sibley Guide to Birds. Alfred A. Knopf, New York. ISBN 0-679-45122-6