Why are Tricolored Blackbird endangered?

What is a tricolored blackbird?

The Tricolored Blackbird closely resembles its near-relative, the Red-winged Blackbird, but males sport white edgings, rather than yellow, on their flashy red wing epaulets. It is nearly endemic to California, where over 95 percent of the global population breeds, mainly in the Central Valley and other points west.

Are tricolored blackbirds endangered?

Farming Tricolor Blackbirds. The Tricolored Blackbird is included on the 2014 State of the Birds Watch List. Already listed as Endangered by the IUCN-World Conservation Union, the species is a now candidate for listing under the U.S. Endangered Species Act (ESA), as well as California’s state ESA.

Why are California’s Tricolored blackbirds nesting in silage fields?

Because of the severe, ongoing drought in California, Tricolored Blackbirds have increasingly turned to nesting in agricultural silage fields, which now hold a significant proportion of the breeding population.

Are there Tricolored blackbirds in California?

Tricolored Blackbird. The Tricolored Blackbird closely resembles its near-relative, the Red-winged Blackbird, but males sport white edgings, rather than yellow, on their flashy red wing epaulets. It is nearly endemic to California, where over 95 percent of the global population breeds, mainly in the Central Valley and other points west.

Why is the population of the tricolored blackbird decreasing?

The population of this species is decreasing rapidly, falling from millions of birds in the 1930s to 400,000 birds in 2008, to fewer than 145,000 birds today, a perilous drop of 66 percent in six years. Many of the habitats once used by Tricolored Blackbirds for nesting and feeding have been lost to urban and agricultural development.

Are there subspecies of the tricolored blackbird?

There are no identified subspecies, although the tricolored blackbird has two fairly distinct population segments: a Southern California population that occurs in southern California south of the Tehachapi Mountains and into northern Baja California, and a Central Valley population segment that occurs throughout the Central Valley.

Is the tricolored blackbird protected?

Formerly, the Tricolored Blackbird was exempt from protections provided by 1918’s Migratory Bird Treaty Act (MBTA), as most blackbirds and their relatives are considered potential agricultural pests. However, in 1985, the Tricolored Blackbird was removed from the list of exempted species and now is fully protected under the MBTA.

Are there Tricolored blackbirds on the Central Coast?

Breeding chronology, movements, and life history observations of tricolored blackbirds in the California Central Coast. Calif. Fish and Game 102: 162-174.

What predators do Tricolored blackbirds have?

Hunting and poisoning to control crop depredation took their toll until the 1960s. Tricolored Blackbirds have many predators, particularly larger birds such as night-herons, ibis, and ravens, and mammals such as coyotes and raccoons.

Is there a tricolored blackbird in California?

Holyoak, Meese, and Graves 2014.pdf Hosea, R. 1986. A population census of the tricolored blackbird, Agelaius tricolor (Audubon), in four counties in the northern Central Valley of California. M.S. Thesis, C.S.U.S. Department of Biological Sciences.

How many Tricolored blackbirds?

Extrapolating from Neff’s estimates, one may conservatively estimate the number of tricolored blackbirds as in the range of 2-3 million birds in the 1930’s. DeHaven and colleagues looked at the abundance of tricolors in the early 1970s and concluded that the species had declined by at least 50% in the 35 years since Neff’s work.

What does a tricolor bird look like?

Tricolored blackbirds look very much like the abundant and widespread red-winged blackbird ( Agelaius phoeniceus ), to which they are closely related. The plumage of adult male tricolors is glossy black and may sometimes show an iridescent blue-green sheen in bright sunlight.

Are tricolored blackbirds omnivores?

Tricolored blackbirds, like other blackbird species, are fundamentally granivores (Orians 1980); however, tricolors consume a wide variety of plant and animal foods (Skorupa, Hothem, and DeHaven 1980), and respond opportunistically to the most abundant, readily available food resource (Payne 1969, Meese 2013).

What are the two subspecies groups of the red-winged blackbird?

Two subspecies groups represent extremes of variation and are reliably distinguished by plumage and differ slightly in song, but intermediate populations exist. Populations in southern Florida may differ in song and plumage and deserve more study. Red-winged Blackbird (Typical) – Agelaius phoeniceus phoeniceusgroup

Why is the tricolored blackbird endangered?

The tricolored blackbird has been the subject of intensive study for several decades due to observed declines and absences from portions of their range, and the Tricolored Blackbird Working Group produced a Conservation Plan in 2007 to guide conservation efforts.

When was the tricolored blackbird statewide survey in California?

Tricolored Blackbird Statewide Survey, 1999 (unpublished). Avery, ML, DeHaven RW. 1982. Bird damage to sunflowers in the Sacramento Valley, California.

What kind of bird is a tricolored blackbird?

A summary of Tricolored Blackbird natural history, efforts to conserve the species, its legal status, and relevant literature. Tricolored blackbirds look very much like the abundant and widespread red-winged blackbird ( Agelaius phoeniceus ), to which they are closely related.

Are there Tricolored blackbirds in the Central Valley?

Settlement and breeding colony characteristics of tricolored blackbirds in 2006 in the Central Valley of California. Meese 2006.pdf Meese, RJ. 2007. Settlement, breeding, productivity and color-banding of tricolored blackbirds in 2007 in the Central Valley of California.

How many nests does a tricolored blackbird have?

Neff (1937) and his assistants studied breeding tricolored blackbirds and found single colonies consisting of up to 282,000 nests, with a maximum number 491,000 nests from a sample of 8 colonies in 1934.

Where do Tricolored blackbirds migrate to?

The bird migrates south during the colder seasons to Mexico and back to northern California during the warmer seasons. The tricolored blackbird does not have any officially recognized subspecies, although there is a population in southern California that may require genetic evaluation.

What does a tricolored blackbird eat?

Tricolored Blackbirds, like other blackbirds and species such as the Bobolink, are grain-eating birds. They also consume a wide variety of plants and insects, and respond opportunistically to the most abundant, readily available food source.