California’s dairy farms provide important ecosystem benefits that support biodiversity—from manure composting and other practices that promote soil health, to creating habitats for birds and other wildlife. As wetlands have continued to disappear, dairy forage fields have become a favorite nesting place for threatened tricolored blackbirds. By allowing the birds to safely nest in fields, farmers have been helping the birds to reproduce and thrive.
“Environmental stewardship is part of our job. We take pride in being caretakers of the land and the animals that live here,” said Simon Vander Woude, who owns and operates Vander Woude Dairy in Merced County.
For the past two years, some of Vander Woude’s forage fields have been the temporary home of tricolored blackbirds, where as many as 20,000 adult birds nested this past season.
The tricolored blackbird is found almost exclusively in California, and is North America's most colonial landbird, a species that prefers to nest in very large groups. The historically abundant tricolored blackbird once nested primarily in wetlands. Due to continued habitat loss, colonies have declined over the past decades, resulting in the bird being added to the state’s list of threatened species. Drought conditions make potential habitats even more limited. Fields used to grow forage crops for dairy cows have become a preferred residence, because the birds can build their nests a few feet above the ground and be near plentiful food and water.
In 2021, more than 170,000 adult tricolored blackbirds were protected on 11 dairy farms across four counties in the San Joaquin Valley. Similarly, the 2020 season saw an estimated total of 177,000 adult birds. Both the 2020 and 2021 seasons represent a record-high number of tricolored blackbirds being protected on dairy farms. When the partnership began in 2015, only 67,000 tricolors were found on dairies.
The last time a statewide survey was conducted to assess the entire population was in 2017, when 178,000 adult birds were counted. An updated statewide survey of tricolored blackbirds is expected in early 2022, which will hopefully document an increase in population, due in no small part to dairy fields and the strong collaboration between dairy farmers and conservationists.
The nesting season for tricolored blackbirds is about 60 days, starting as early as February. Typically, nesting of these birds only happens on a dozen or so of the hundreds of dairies across the Central Valley, but for those few dairies where nesting occurs, it can pose a real challenge. Nesting coincides with harvest season, forcing the farmers to delay or forgo harvests. During the delay, crops dry out, making feed less nutritious and often unusable, leaving farmers struggling to find other sources of quality feed for their cows.
For the last several years, Audubon California has partnered with USDA’s Natural Resources Conservation Service (NRCS), and dairy organizations and conservation groups to support farmers as they protect the threatened tricolored blackbird species. Since 2015, NRCS has provided funding to help dairy farmers recoup some of their financial losses caused by delaying or forgoing harvest.
While this year’s report is promising for the species, there is no doubt that climate change and worsening drought conditions will continue to pose challenges to tricolored blackbirds and farmers, making ongoing partnership essential. Grant partners include Audubon California, California Dairy Research Foundation, California Farm Bureau Federation, Dairy Cares, California Dairy Campaign, Milk Producers Council, and Western United Dairies. Partners provide coordinated outreach support, research, and partial matching funds.
Research efforts continue to explore ways to draw the birds to other more suitable habitats or otherwise minimize financial losses to dairy farms. However, at least in the short term, California dairy farmers know their fields might very likely become the temporary home for thousands of birds and their young.
“The fact that the birds return to nest on dairy farms year after year shows how important our forage fields are to the species’ survival and to biodiversity as a whole,” said Vander Woude.
California dairy farmers play an important role in protecting the state’s rich biodiversity. Watch the video to learn more.