Tag Archives | Tricolored Blackbird

Status of the Tricolored Blackbird and Yellow-billed Magpie

Tricolored Blackbird by David Bogener

Tricolored Blackbird by David Bogener

This month Dan Airola will provide recent status information on the Tricolored Blackbird and Yellow-billed Magpie, two Central Valley species that have declined substantially in recent years. Blackbird population loss has resulted from habitat loss, nest destruction during agricultural harvest, and loss of insect prey due to insecticide use. The successful proposal to list the species under the state Endangered Species Act sparked research and conservation programs. Dan recounts this recent history and the successful efforts that have resulted in modest but important population increase. The population of the state-endemic Yellow-billed Magpie declined by over 80% in California since the arrival of West Nile virus in the early 2000’s, and did not develop resistance, unlike some other species. Dan’s recent studies reveal key habitat relationships and an apparent incipient recovery in the sizable urban Sacramento population.

Dan Airola is a Wildlife Biologist and Ornithologist who has worked for over 40 years in research and conservation of at-risk species birds in Northern California. In addition to long-term research on the tricolor and magpie, Dan maintains a 30-year study of Sacramento’s Purple Martins and has also studied Swainson’s Hawks, Turkey Vultures, Osprey, fire-adapted forest species, migrant songbirds, and diving ducks. Dan also serves the Central Valley Bird Club as a Director, Conservation Chair, and editor of the journal Central Valley Birds.

Wintu Audubon Society is inviting you to a scheduled Zoom meeting.

Topic: Status of the Tricolored Blackbird and Yellow-billed Magpie
Time: Nov 8, 2023 07:00 PM Pacific Time (US and Canada)

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Meeting ID: 849 3595 9479

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Audubon California Working Lands Program

Audubon California will update us on the Working Lands program. This work encourages bird-friendly practices on farms, wetlands and other managed lands in the Central Valley. It is done by cultivating relationships with landowners, advocating for statewide policies that secure water and habitat for birds, and engaging our grassroots network in their communities. Our work provides protection for focal species like the Long-billed Curlew, Tricolored Blackbird, and Western Grebe. The presentation will also focus on what we know, and fear, about the impact of the mega-drought on birds, especially in the critically important Pacific Flyway as it passes through the Central Valley.

Topic: Audubon California “Working Lands” Program
Time: Oct 12, 2022 07:00 PM Pacific Time (US and Canada)

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Meeting ID: 848 9517 0010
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Meeting ID: 848 9517 0010
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Numbers Matter for These Birds

Tricolored Blackbird by David Bogener

Tricolored Blackbird photo by David Bogener

Last month local birders joined in a state-wide survey of tricolored blackbirds. These birds look much like their more common and widespread relatives, the red-winged blackbirds, and they are even found in similar marshy habitats. But the two speak different languages and have markedly different lifestyles.

These are the sounds of the Red-winged Blackbird:

These are the sounds of the Tricolored Blackbird:

The survey is conducted statewide in just three days. This all-at-once survey approach minimizes recounting the birds as they move. And move they do!

Tricolors begin nesting in early spring in southern California and the San Joaquin Valley. Then they move northward and by late spring and early summer are ready to undertake a second nesting, much of it in the Sacramento River watershed. This year the survey in early April found no tricolored blackbirds in southern Shasta County. Two weeks later the nesters moved in: 10,000+ were reported.

Those birds were descending on a field of Himalayan blackberry. Tricolors have been versatile, and as historical marshes of tules and cattails have gone dry, they have adopted a wide range of nesting vegetation, including nettles, mallows, triticale, and blackberries. When they find a field that looks promising, they swarm into it by the hundreds, thousands, and tens of thousands.

If you visit a local pond this time of year, you are apt to see a sprinkling of red-winged blackbirds perched on the tules, perhaps singing their reedy but musical song and showing off their bright epaulettes, vermillion edged with yellow. Below them are the females, hidden with their brown plumage as they warm their eggs in reed-hung hide-aways.

These red-wing colonies might stretch thirty feet from one perched male to the next. Tricolors, on the other hand, go for high-density. The males are likely perched a mere yard from one another, and there are probably two females on two nests beneath each male. This high-density nesting offers a potential advantage.

While the bright and busy colony, along with the tricolors’ raucous, obnoxious blatting, may draw predators, the sheer number of birds overwhelms most local predators. The nearby cats and snakes can only eat so many nestlings. The vast majority survive.

Unless the killing is mechanized. The flock of over 10,000 that arrived in our county seems huge, but surveys in the 1930’s documented colonies with a quarter to a half million nests! Since then, numbers have steadily tumbled. When triticale replaced tules, tricolors adopted the new fields; farmers reacted to the hungry hordes with poisoned grain and market hunts. Those actions are now outlawed, but, despite many positive farmer-conservationist collaborations, harvesting of grain while birds are still in their nests sometimes continues, wiping out entire reproductive colonies. Most irrevocably, the inexorable conversion of marshes into row crops, orchards, homes, and shopping centers reduces habitat on a wide and lasting scale.

Still, 10,000 birds is enough to make a successful colony. Enough, in fact, to raise the seamy side of reproductive abundance. Tricolors try to nest near plenty of grain and insects, but their numbers can overwhelm not only local predators, but also local food supplies. This creates hunger at home, a problem that different species face differently. Underfed eagle and owl chicks eat their younger siblings. Wolves reduce their offspring by limiting reproduction to one pair in the pack. Observations indicate that tricolored blackbird mothers, rather than starve their whole broods, will remove some chicks to be able to feed the others. It’s not a pleasant reality, but one that successful reproduction can force.

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