Tricolor blackbird
| Tricolor blackbird | ||||||||||||
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Dreifarbenstärling ( Agelaius tricolor ), male |
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| Scientific name | ||||||||||||
| Agelaius tricolor | ||||||||||||
| ( Audubon , 1837) |
The three-colored blackbird ( Agelaius tricolor ) is a songbird species from the family of blackbirds (Icteridae) found in North America .
description
Appearance
Three-colored blackbirds reach an average total length of 22.3 centimeters for the males and 18.5 centimeters for the females. The weight is 60.0 to 79.0 grams for the males and 46.0 to 54.5 grams for the females. There is a clear sexual dimorphism between the sexes . The males are generally glossy black and sometimes show a slightly bluish tinge. The superimposed red and pure white stripes on the arm covers are typical of the species. This distinguishes them from the similar red-shouldered blackbird ( Agelaius phoeniceus ), in which the light stripe has a dirty white to yellowish color. Female three-colored blackbirds are evenly colored black-gray with almost no drawing. Only the throat is gray-white. The iris is dark brown in both sexes. Legs, feet and beak are black.
Vocalizations
The male's song consists of a hard, not very musical sequence of tones that sounds like a growl.
distribution and habitat
The year-round populated area of distribution covers a narrow strip in western California to northern Baja California . Narrowly limited, isolated breeding areas are also located in the US states of Washington , Oregon and Nevada . The original habitat of the kind are marshes with cattails - ( Typha ) or Sims vegetation ( Scirpus ). It has recently also been found on pastures, rice fields and other irrigated agricultural areas and occurs at altitudes of up to 1,300 meters.
Way of life
The birds live together in very large colonies. They are mostly monogamous . Sometimes the males mate with up to four females. Tricolor blackbird feed on insects and seeds, including rice .
The nest is built from grass in a cup-shaped manner by the females from March and covered with a fine layer of mud. It is preferably placed in willow ( Salix ) or Rubus bushes at heights of up to three meters. The clutch usually consists of four eggs. These are pale blue-green in color with a few small black spots and lines. They are hatched within 11 to 12 days. The females feed the nestlings, which fly out after 12 to 13 days and are then looked after by the male. A second brood only occurs occasionally in autumn. The red- eyed cowbird ( Molothrus aeneus ) sometimes appears as a brood parasite .
Hazard and protection
The population of the three-colored blackbird was classified in the IUCN Red List of Threatened Species in 2016 as " Endangered (EN) " = "critically endangered". In 1934 its number was estimated at 700,000 animals. The species was considered an agricultural pest until the 1960s and large numbers were poisoned. This, as well as the loss of habitat through agricultural use with the use of pesticides, resulted in the following drastic decline in the number of individuals in California:
- 1994: 370,000
- 1997: 233,000
- 2000: 162,000
After a protection program was decided, the population recovered and was given in 2005 with 257,000 and 2010 with 395,000 individuals.
swell
literature
- Josep del Hoyo , Andrew Elliott, David A. Christie: Handbook of the Birds of the World, Tanagers to New World Blackbirds. Volume 16, Lynx Edicions, 2011, ISBN 978-84-96553-78-1 .
Individual evidence
- ^ Fraga, R. (2016). Tricolored Blackbird (Agelaius tricolor). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, DA & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/62298 on April 18, 2016).
- ↑ Agelaius tricolor in the Red List of Threatened Species of the IUCN 2016. Posted by: BirdLife International, 2016. Accessed March 8, 2018th
Web links
- Dreifarbenstärling (Agelaius tricolor) in the Encyclopedia of Life . Retrieved August 11, 2017.