Tricolored blackbirds are disappearing faster than thought
The tricolored blackbird was once among the most common birds in California, with vast colonies of the colorful and highly gregarious species nesting and foraging year-round in marshes and rangelands.
Scientists have been worried about a decline in tricolored blackbirds for years now, and the latest statewide surveys show that things are worse than they thought. The entire population dropped from an estimated 400,000 birds in 2008 to roughly 258,000 in 2011.
“The next statewide survey will be conducted in 2014, and the results will be alarming,” said Robert Meese, staff research associate at UC Davis’ department of environmental science and policy. “The tricolored blackbird population is in free-fall due to chronically poor reproductive success since 2006.”
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The two worst years of reproduction output ever measured were 2012 and 2013, according to Meese, who has been studying tricolored blackbirds since 2005 and has banded more than 52,000 of them.
“The problem is that these birds do not have enough to eat,” he said. “They exist in a small number of fairly large colonies of individuals who fly no more than five miles to find insects they depend on.”
“Today, they are typically found in agricultural settings where insects are suppressed,” he said. “As a result, they have become the modern ecological equivalent of the passenger pigeon.”
If the trend continues, the species already designated a federal bird of conservation concern and a California state species of special concern could be reduced to 50,000 birds statewide within a decade, Meese said.
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As part of an effort to save the birds from extirpation in California, Audubon California and the U.S. Department of Agriculture’s Natural Resources Conservation Service are leading a program that pays dairy farmers to delay harvesting their silage crops through the nesting season.
Earlier this year, six Tulare and Kern County farmers were paid about $393 per acre for the resulting disruptions to their labor schedules and drop in the quality of grain.
The voluntary program made the farmers about two weeks later than usual in getting their crops harvested, allowing tricolored blackbirds to breed and then leave the area.
“It’s not an ultimate solution,” said Anita Brown, spokeswoman for the U.S. Department of Agriculture. “But by working together, farmers are going forward so that we can eat and birds are nesting for the survival of their species.”
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