For Immediate Release, February 3, 2015

Contact: Jeff Miller, (510) 499-9185 or jmiller@biologicaldiversity.org

Federal Protection Sought for California’s Tricolored Blackbirds

Latest Surveys Show 87 Percent Population Decline Since 1930s

SACRAMENTO, Calif.— The Center for Biological Diversity today filed a petition to protect the tricolored blackbird — which once formed massive nesting colonies in California’s Central Valley — as endangered under the federal Endangered Species Act. The state of California recently enacted emergency protections for tricolored blackbirds, a species that has declined dramatically due to destruction of wetlands and native grasslands, shooting, pesticide use, and nest destruction during mowing and harvest of crops used as nesting sites.

“If tricolored blackbirds are going to survive for the long haul, they need the help only the Endangered Species Act can provide. First and foremost, federal protections are needed to halt the ongoing destruction of large nesting colonies, shooting and other threats,” said the Center’s Jeff Miller. “The tricolored blackbird population can’t recover without nest protection, because a small number of breeding colonies can contain most of the entire population. Unless there are immediate protections and limits on killing, this unique bird could go the way of the passenger pigeon.”

Tricoloreds form the largest breeding colonies of any North American land bird, with a single colony often consisting of tens of thousands of birds. These large breeding colonies are a defense again predation. In the 1800s one observer described a wintering tricolored flock in Solano County as “numbering so many thousands as to darken the sky for some distance by their masses,” and in the 1930s a biologist reported a flock of more than a million tricoloreds in the Sacramento Valley alone.

Comprehensive statewide surveys in 2008 found only 395,000 tricolored blackbirds. Tricolored numbers declined to 259,000 in 2011 and only 145,000 were documented in 2014 — the smallest population ever recorded.

Background
The tricolored blackbird (Agelaius tricolor) is a medium-sized bird that breeds in dense colonies in California’s Central Valley, coast ranges and Southern California. The primary breeding range is the Sacramento and San Joaquin valleys. Adult males are a glossy blue-black with striking red and white shoulder patches, while females are mostly black with grayish streaks, with a small but distinct reddish shoulder patch. Tricolored blackbirds typically eat insects but will also take grains, snails and small clams.

Forced from their natural nesting sites by conversion of wetlands and native grasslands in the Central Valley to urban and agricultural development, many tricoloreds have adapted by nesting in agricultural crops — typically dairy silage fields. Crop harvesting often coincides with egg laying and hatching, and many tricolored eggs and nests are destroyed during harvests.

Recent surveys documented up to half the entire tricolored population nesting in just two colonies in the Central Valley in dairy silage fields. Thousands of these nests containing eggs and hatchlings were mowed down during harvest — even though bird nests and eggs are supposed to be protected under California Fish and Game Code. An unknown number of adult tricoloreds are also killed each year by rice farmers, who are allowed to shoot flocks of blackbirds to protect their crops.

Over the past decade the California Department of Fish and Wildlife and other partners have initiated voluntary measures to save tricolor nests from destruction during crop harvest by making crop purchases or reimbursing farmers for delayed harvest on private agricultural lands where tricolors nest. Unfortunately not all landowners with tricolor nesting colonies have cooperated, and these measures have not stopped the decline of the species or prevented destruction of tricolor nests on many dairy farms and other agricultural lands in the Central Valley. In 2011 more than half of all tricolor nests in silage fields were destroyed, despite efforts to contact farmers and coordinate buyouts of harvest delays.

In December 2014, in response to a petition filed by the Center for Biological Diversity, the California Fish and Game Commission enacted emergency protections for tricolored blackbirds. The state has protected tricoloreds under the California Endangered Species Act for 180 days. The California Department of Fish and Wildlife is evaluating the listing petition and will recommend whether to protect tricoloreds on a permanent basis and impose limits on activities that kill or injure tricolors.

Read more about the Center’s work for tricolored blackbirds.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 800,000 members and online activists dedicated to the protection of endangered species and wild places.


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