The Tricolored Blackbird is North America's most colonial nesting landbird. Found almost exclusively in California, a single breeding colony can teem with over 35,000 birds, sometimes all settled into a single field or small wetland to raise their young. While similar to the more widespread Red-winged Blackbird, the male Tricolored Blackbird is distinguished by its red shoulder patch with a bright white wing-bar.
In the 19th century, Tricolored Blackbird flocks were described as numerous and often consisted of hundreds of thousands of birds. Since then, the population has declined from several million to approximately 177,000 today. Over a 10-year period from 2007 to 2016, it is estimated the population declined by as much as 34%.
There are many reasons for this decline. But the loss of native wetland and nearby foraging habitats along the coast and in the Central Valley is the main issue. In more recent years, the species has become dependent on agricultural lands, with most of the largest colonies nesting in grain fields. A real dilemma develops as Tricolored Blackbird young typically have not yet left the nest before the time farmers need to harvest their crop, and harvesting destroys Tricolored Blackbird nests and young. In some cases, tens of thousands of nests have been lost in a single field.
Each year, these birds gather in highly social colonies to raise their young throughout the San Joaquin Valley, Sacramento Valley, Sierra Foothills, Central Coast, and Southern California. However, with the continuing loss of habitat and the places they need to survive are becoming scarcer. As a result of this continued habitat loss and drastic population decline, Tricolored Blackbirds were recently listed under California's Endangered Species Act thus highlighting the recovery of this species is more critical than ever.
Farms and ranches will play a critical role in conserving Tricolored Blackbirds across the Central Valley.
Watch this video by Audubon's partner Dairy Cares in the Central Valley
Thanks to our agricultural partners,100% of thirteen Tricolored Blackbird colonies across the San Joaquin Valley in California were protected this year.
In the sixth year of the Audubon Summer Conservation Program, we worked closely with dairy producers to protect 100% of the known 15 Tricolored Blackbird colonies on agricultural fields across four counties.
Despite small breeding colonies in neighboring states, Tricolored Blackbirds are California's blackbird. Over 95 percent of the global population resides in the state. While anyone ever seeing a teeming flock of “trikes” feeding or in flight might have a hard time believing, the bird was listed as threatened under the California Endangered Species Act in 2019. However, Audubon research indicates that populations may be beginning to recover.
As recently as 1930, millions of Tricolored Blackbirds darkened the skies near Central Valley wetlands. As marshes were drained, the birds moved onto agricultural land, especially wheat fields. Farmers typically harvest their crop before nestlings have fledged, even wiping out the young of entire colonies in a single day as harvesting machinery moves across an occupied field. In surveys conducted from 2005 through 2009, less than half of colonies escaped destruction of their nesting areas.
For the past eight years, Audubon has worked together with farmers, the California Department of Fish and Wildlife, Natural Resources Conservation Service and other partner organizations to locate colonies and encourage growers, through financial incentives, to postpone harvests until nestlings had fledged. In a study recently published in the journal Western Field Ornithologists, we found that this public-private partnership has been highly successful: from 2015 to 2022, nearly 100 percent of nesting attempts on agricultural land were conserved, and the number of birds nesting in grain fields increased by as much as 100,000. The reported increase in the population was confirmed during the most recent stateside survey in 2022. This survey is a coordinated voluntary effort, involving many chapter members across the state, to survey suitable habitat areas for birds resulting in a snapshot in time that tells us approximately how many birds are in the population. Protection of the most at-risk nesting sites is contributing to a bump in Tricolored Blackbird populations statewide, but innovative conservation efforts must be continued if the species is to recover fully.
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