Newswise — ITHACA, N.Y. –When scientists first proposed adding the Tricolored Blackbird to the California endangered species list in 2004, they had a problem. Tricolored Blackbirds nest in large colonies that can move from year to year, and because the locations of these colonies in any given year may not be known, existing survey data were not enough to convince the California Fish and Game Commission to approve the listing.

In 2015 the species was again under consideration for protection under the California Endangered Species Act. This time, however, partners at California Audubon were armed with new information, thanks largely to the work of Dr. Orin Robinson—a Cornell Lab of Ornithology Postdoctoral Fellow in Conservation Science who has been studying Tricolored Blackbirds for the past two years. 

Robinson’s work combined data in eBird, a citizen-science project logging millions of bird sightings, with survey data from partners at UC Davis to develop new trend estimates for the state’s Tricolored Blackbird population. By combining these data sets, Robinson developed a statistically reliable population model showing Tricolored Blackbirds declined more than 33 percent during just the past 10 years.

Robinson’s research was the key piece of evidence cited by the State of California to approve state Endangered Species Act protections for Tricolored Blackbirds this past April.


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Journal Link: Biological Conservation