Monday, 18 April 2011

Tricoloured blackbird

Agelaius tricolor

(Photo from Animal Photo Album)

Common name:
tricoloured blackbird (en); iratauá-tricolor (pt): carouge de Californie (fr); turpial capitán (es); dreifarbenstärling (de)

Order Passeriformes
Family Icteridae

This species is found along the Pacific coast of North America, from southern Oregon to California and Nevada, in the United States, and into Baja California and El Rosario in Mexico.

Tricoloured blackbirds are 18-24 cm long and have a wingspan of 30-35 cm. They weigh 59-68 g.

These birds breed in freshwater marshes with tall emergent vegetation, in upland habitats and in silage fields. They forage in agricultural areas, particularly where livestock are present and grass is short, and show a preference for roosting in marshes. They are found from sea level up to an altitude of 1.300 m.


An opportunistic forager, the tricoloured blackbird takes any locally abundant insect including grasshoppers, beetles and weevils, caddis fly larvae, moth and butterfly larvae, dragonfly larvae, and lake shore midges, as well as grains, snails, and small clams.

These birds breed in April-July. They are polygynous with 1-4 females per male. Each females build the nests alone, a shallow, open cup made with dry leaves which are dipped in water and woven around strong, upright plant stems, usually around 1 m above the ground. The nest is lined with mud and softer materials. There the female lays 3-5 eggs which she incubates alone for 11-12 days. The chicks are fed by both parents and fledge 10-14 days after hatching.

IUCN status - EN (Endangered)
This species has a relatively small breeding range and the global population of 250.000 individuals is believed to be undergoing very rapid declines owing to loss of nesting habitat, low reproductive success in native habitats and complete breeding failure in harvested agricultural fields. Additionally, herbicide spraying and contaminated water are suspected to have caused complete breeding failure in several colonies. Because breeding success is so poor in native wetlands, protection of these habitats will not reverse population declines in the species, so conservation measures must focus on agricultural land and upland habitats as well.

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