Project Lead: California Audubon Society
KEY TAKE-A-WAYS
• A partnership between Dairy Cares, Western United Dairies, Audubon California, and numerous other groups was formed in 2015 to protect, restore, and enhance the habitat of the Tricolored Blackbird in the San Joaquin Valley, where nests on dairy farms are often destroyed during harvest.
• Compared with conservation efforts from 2005 to 2009, the Regional Conservation Partnership Program (RCPP) and related actions were highly successful in minimizing losses of Tricolored Blackbird colonies to dairy farm silage harvest. From 2017 to 2021, the number of colonies in silage increased by two-thirds and the number of breeding adults increased by 127%.
• Conservation efforts must continue to help protect Tricolored Blackbirds, including the continued partnership between public and private organizations to secure funding that is critical for Tricolor protection.
BACKGROUND AND OBJECTIVE
Tricolored Blackbirds often make nests in fields of triticale that are being grown for dairy silage in the San Joaquin Valley. Their population has been in decline over the last three decades due to many factors, including destruction of breeding colonies during agricultural harvest. Independent analyses estimated a population decline of 40% between 2008 and 2017. The species was listed under the California Endangered Species Act, and their penchant for nesting in triticale fields has prompted concerns over the species’ conservation. Efforts to protect colonies nesting on farms started in the early 1990s but were sporadic due to inadequate and inconsistent funding and lack of legal incentives for protection. In 2015, the National Resources Conservation Service awarded $1.1 mil under its Regional Conservation Partnership Program (RCPP) to start a partnership consisting of Dairy Cares, Audubon California, the California Farm Bureau Federation, Sustainable Conservation, and Western United Dairies to protect, restore, and enhance Tricolor habitat in the San Joaquin Valley. This study evaluated the effectives of the RCPP along with other programs aimed at Tricolor conservation in the San Joaquin Valley.
METHODS, FINDINGS AND OUTCOMES
The numbers of colonies and breeding individuals in silage colonies that were conserved or lost to harvest were compared from 2005 to 2009 and 2015 to 2022. From 2005 to 2009, 58% of the total number of Tricolored Blackbirds (approximately 133,000 birds) were conserved, whereas 42% of the total population were lost to silage harvest. The researchers estimated that roughly 11% of the species’ productivity in California was lost during these five years. From 2015 to 2021, conservation efforts appear to be highly effective with 93% of colonies protected and an annual average of 119,500 breeding birds (96% of all breeders with known outcomes) were protected. From 2017 to 2021, the number of colonies in silage increased by two-thirds with the number of breeding adults increased by 99,00 (127%). Over the three time periods for which data are available, the cost of protection per breeding bird nearly quintupled suggesting that funding efforts are clearly associated with conservation.
CONCLUSIONS
The RCPP and related actions were highly successful in minimizing losses of Tricolor colonies to silage harvesting. This success is attributable to several factors. First, the RCPP provided much needed multi-year funding for conservation efforts. Listing the species under the California Endangered Species Act prompted attention and funding, as well as added incentives for dairy producer participation in conservation efforts.
So far, good progress has been made by the dairy industry in bird conservation, however efforts have yet to restore the population to the full goal of 700,000 Tricolors. Recovery efforts will require a continued partnership between public and private organizations to secure funding, conduct research, and spread awareness of this issue. The research and educational aspects of this project are ongoing through CDRF between 2020-2024. results.