Biologist Ian Souza-Cole stands with his back to a balmy, manure-scented north wind sweeping over California’s San Joaquin Valley. It’s early May, and he is on a large dairy farm near the town of Planada, staring intently across a field of triticale, a wheat-rye hybrid favored as feed for milk cows.
Overhead and all around, black specks zip through the air like debris in a hurricane. Getting a closer look through his binoculars, Souza-Cole points at one of them. “She’s carrying food,” he says.
Souza-Cole, a senior coordinator with Audubon California’s Working Lands Program, is here to visit a nesting colony of about 25,000 adult Tricolored Blackbirds. Like shoppers in a supermarket parking lot, the birds beeline back and forth between their nests in the triticale and a barn where several thousand cows feed. Dark brown females carry insects and corn plucked out of cattle troughs to feed their chicks. Males, whose black wings bear the white-and-red splash that gives Tricolors their name, forage mostly for themselves.
The “trikes,” as biologists call these beautiful blackbirds, colonized this property in March. Since then, Souza-Cole has visited weekly. As a protected species, the birds complicate matters for landowners. What Souza-Cole and this farm’s owner want to know is when they will move on. By observing the foraging behavior of the adults and studying a chick through his binoculars, Souza-Cole estimates the colony will be here another three weeks. “Then we can release the field to the farmer,” he says.
Not long ago, dairy producers routinely motored their harvesters through fields where the blackbirds were nesting, sometimes killing thousands of flightless chicks in minutes. This carnage threatened the survival of the species, whose numbers, historically 2 million to 3 million, plunged through the 20th century, bottoming out at an estimated 145,000 in 2014.
In 2015, as experts recognized that extinction was a real possibility for the species, Audubon California and a network of researchers and government wildlife managers initiated a program aimed at reversing the decline. The work involves surveying known nesting areas each spring to find colonies that have settled in grain fields, then contacting the farm owners and paying them to delay their harvest. The idea is to guarantee the blackbirds a safe haven until their chicks fledge.
That first spring, using funding from the U.S. Department of Agriculture, the initiative protected 67,000 adult birds and their young across 5 nesting colonies, according to Xerónimo Castañeda, working lands program director for Audubon California. Those figures have grown almost every spring, he says, with a big jump from 77,000 birds protected in 2017 to 158,000 in 2019. That spike straddled the year that the Tricolored Blackbird was listed as threatened under the California Endangered Species Act. The Tricolors’ 2018 upgrade to protected status meant farmers could no longer harm them, even if they received no compensation for lost crops. Still, the program continued to make payouts in the interest of maintaining amicable relations between farmers, blackbirds, and their advocates.
Now a decade old, the initiative—which has received additional funding from the California Department of Fish and Wildlife—has probably prevented the deaths of at least half a million chicks. Last spring the buyout program protected an estimated 235,000 adults in San Joaquin Valley fields alone. This year’s preliminary tally sits at around 200,000 nesting adults.
“We’ve been a lot better at protecting colonies, ensuring that they’re found early,” Castañeda says. “We’ve been able to protect more colonies and more birds, and the population is starting to see a little uptick.”
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he vast majority of Tricolored Blackbirds spend their whole lives in California. A handful breed in Oregon, Washington, Nevada, and Baja California, and at least 20 of the birds were spotted last year in Idaho. Most, however, nest in the San Joaquin Valley, and many are known to breed a second time in the early summer months—often 50 to 100 miles north in the wetlands and willows of the Sacramento Valley. It’s here, too, that the birds feed on rice in the fall. They often browse the paddies alongside other blackbirds—including the very similar Red-winged Blackbird—that farmers can legally cull as pests. This has inevitably led to losses of Tricolors over the years.
Although the species’ native nesting habitat has been almost entirely removed from California, they’ve adapted with varying success to shifting land use. Where vineyards and orchards have replaced grassland and marsh, the blackbirds have mostly disappeared. But in other cases, they’ve gamely gone along with habitat changes, combing the landscape for suitable sites each year. In 2022, for instance, an estimated one-quarter of the population nested in invasive Himalayan blackberry thickets.
Certain grain crops, too, have proven attractive for nesting. In the 1980s, the rapid expansion of dairy farming in the San Joaquin Valley checkerboarded the region with triticale, wheat, and other grains used to feed the cows, often after being fermented into a nourishing product called silage. Blackbirds took a liking to these fields, mostly because they’re near barns filled with troughs of nutritious corn and swarms of insects.
Trouble was, the silage crops were generally ready for harvest at the peak of the nesting season, often when the chicks had just hatched. Across the valley, entire colonies were mulched by grain combines. Most adults would fly safely away, but nests and juveniles were totally wiped out. By the mid-1990s, these massacres had become the main threat to the species’ survival. “The reproductive success was reduced to zero,” says Robert Meese, a retired U.C. Davis staff research associate with 20 years of experience studying Tricolored Blackbirds.
The collaborative work with farmers has all but eliminated that once-existential threat. There were no known silage mortality events in the past three years, marking a promising change of course for a species that, until just a decade ago, was trending toward zero. Higher counts reflect more accurate surveying in recent seasons, Meese says, but the comeback is real, and it’s a sign that conservation measures are working.
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fter completing his weekly check-in at the Planada dairy, Souza-Cole drives southwest for about 30 minutes, aiming for a cluster of Tricolor colonies along arrow-straight Sandy Mush Road. The first one he visits is safely established on the Merced National Wildlife Refuge, where some 20,000 adults have built their nests in a mustard field.
A few miles down the road, he pulls into Diamond J Dairy, where about 10,000 Tricolors have bedded down in the farm’s triticale. Co-owner Luciana Jonkman says she appreciates the return visitors despite the complications they bring. “This is just where they’re living,” Jonkman says. “This is part of the ecosystem.”
Still, the birds, which occupy about 50 acres, will cause a cascade of financial impacts through the spring and summer. First, postponing the triticale harvest will make the grain too dry for fermentation into silage, so Jonkman will need to buy supplementary feed. And pushing back the harvest—the triticale can still be sold for dry grain and straw—she must also delay planting the same fields with feed corn. By that point, the soil will be drier and may require extra irrigation.
And that’s not all. Jonkman looks across the field, busy with blackbirds. She grins and gestures at the barn, where trikes are scarfing down her cows’ corn. “This dairy is like a buffet at Vegas,” she says.
Before the state pitched in matching funds, the payouts came nowhere near to meeting these expenses, Jonkman says. This year, according to Castañeda, joint state and federal contributions will add up to about $1,600 per idled acre—roughly double the rate a few years ago. “That potentially gets us closer to full compensation,” Jonkman says.
With all the scouting, outreach, and fundraising involved, paying farmers to postpone harvests is a constant uphill push, and not the ideal model for sustainable blackbird conservation. The optimal outcome, Castañeda and others say, is to develop a reliable strategy for drawing the birds away from dairy farms during the nesting season. One option could be to plant crops that make attractive nesting habitat, whether grains or certain wild grasses, on protected lands, such as wildlife refuges. Early tests of this approach haven’t panned out, but Castañeda thinks that, just as backyard birds don’t immediately notice a feeder, it may just take time and repetition to gain the birds’ attention.
This season Souza-Cole has been field testing decoys as another tactic to lure nesting blackbirds away from dairies. Early this spring, he posted about 70 of them on sticks in a marsh at the Kern National Wildlife Refuge, along with speakers that squawked recordings of the birds’ cat-like caw. This failed to draw in the flocks, so Souza-Cole plans to fine-tune his techniques next year with earlier deployment and by playing a wider variety of recorded Tricolor sounds.
For now, silage fields provide some of the San Joaquin Valley’s most productive Tricolored Blackbird habitat, and the overlap between nesting colonies and dairy farms will probably increase as the population grows. While the birds have the law on their on their side no matter where in the state they nest, punishing farmers is an unwanted last resort to protecting the species. “Nobody’s really interested in that fight,” says Souza-Cole as he walks back to his car to continue his day of surveys. “It’s preferable to create a system where everybody wins.”
