A comprehensive survey of rare Tricolored Blackbirds in California has confirmed that the population of the rare bird has declined more than 30 percent in the last three years. The Tricolored Blackbird, which once numbered in the millions, lives almost entirely in California. The 2011 survey, conducted by Audubon California with the help of more than 100 volunteers, identified about 259,000 birds at 138 sites in 29 counties. In 2008, a similar survey counted approximately 395,000 Tricolored Blackbirds in California.

“It’s disappointing to see this remarkable bird continue to struggle to survive in California,” said Graham Chisholm, executive director of Audubon California. “With drought conditions and ongoing habitat challenges, the population is experiencing wide fluctuations in size, and that’s a real concern for a population this small.”

The survey confirmed that the Tricolored Blackbird continues to mostly reside in California’s San Joaquin Valley. A full 89 percent of the birds were found there during the survey. The survey also confirmed that the birds continue to struggle in southern California. The Tricolored Blackbird, once the most common bird in San Diego County, only numbers about 6,000 in the southern half of the state.

The survey report identifies low breeding productivity as the potential main reason for the dramatic decline in Tricolored Blackbird numbers. Several years of drought certainly played a role in that reduced productivity, as did colony failure. The report notes that large breeding colonies on private farms continue to be lost as fields are harvested before young birds have fledged.

An agreement among public agencies, conservation groups and agricultural representatives to  form the Tricolored Blackbird Working Group has brought diverse parties together to protect and grow the state’s struggling Tricolored Blackbird population. Since then, Audubon California has negotiated a number of agreements to protect large breeding colonies on private farms, and is developing strategies to create new breeding habitat on public lands.

Just this spring, Audubon California secured the safety of several large colonies of rare Tricolored Blackbirds on private property. In all, the agreements resulted in the protection of the breeding production of at least 50,000 birds.

“Because this bird lives almost entirely in California, we have the responsibility to make sure its future is secure,” said Chisholm.