Tricolored Blackbirds: The Delta's Passenger Pigeon | KCET
Tricolored Blackbirds: The Delta's Passenger Pigeon
An explanatory series focusing on one of the most complex issues facing California: water sharing. And at its core is the Sacramento-San Joaquin Bay Delta. Stay with kcet.org/baydelta for all the project's stories.
It's a warm June afternoon in the northern Sacramento Delta. In the Vic Fazio Yolo Bypass Wildlife Area west of Sacramento, the air is heavy with humidity and the smell of foliage. Slow-walking a levee road overgrown with Queen Anne's lace and scratchy star thistle, I flinch as one male red-winged blackbird after another flies up out of the tules along the road, displaying their bright red wing patches as they confront me.
One of the males is subtly different, a bit darker and glossier, its cry more raucous than musical. I haven't brought binoculars, but they'd be close to useless at this range: the bird's about a dozen feet away. It's moving a bit too fast to make it easy, but I look closely at its display patches.
And then I see it: a bright area just below the red on its wing. On a male redwing, that patch would be a bright yellow, but on this bird it's white. A subtle difference but an important one: this male is a tricolored blackbird, Agelaius tricolor, California's passenger pigeon. It used to be the most common bird in California. And 20 years from now there may not be any of its kind left on the planet.
The Yolo Bypass used to be prime habitat for tricolored blackbirds: they once massed here in the millions during breeding season. I didn't particularly expect to see one here. Not only are tricoloreds a lot rarer than they used to be, but summer's when they tend to disperse across the state. The Delta is more wintering habitat for them: back in the day, according to the literature, they used to darken the skies here, breeding in massive colonies of hundreds of thousands of mated pairs. Sometimes millions. The din of so many noisy birds must have been unimaginable.
And then the same thing happened to the tricolored blackbirds that happened to most of the rest of the species that were here when European settlers showed up. Namely, European settlers showed up, and started making massive changes to the landscape to suit our own whims. Like the California grizzly and the Ridgway's rail, we sometimes set out to kill tricolored blackbirds deliberately, either for meat markets (though they're small enough that they seem hardly worth the effort) or as perceived agricultural pests. Mainly, though, we just turned the floodplain habitat they need to breed into something else: farms, cities, parking lots, reclaimed wetlands from which the water has mostly been diverted. From millions upon millions, the bird's population fell to around 145,000 by 2014.
The Vic Fazio Wildlife Area in the Yolo Bypass is one of those reclaimed wetlands, about 17,000 acres of former wild floodplain now managed for waterfowl habitat. Though it's considered a wetland restoration project, the interpretive signs here are careful to point out that the wetland that used to thrive here can never be restored. Instead, the California Department of Fish and Wildlife fills individual tracts here with water when the Sacramento River is in winter flood, providing habitat for migrating waterfowl.
In June, the place looks a little parched, but still full of life. I'm here with a friend. Right now she's taking a break napping in a stand of tules. An hour ago we walked an interpretive trail through a patch of demonstration wetlands kept full of water, alive with dragonflies and algae. Monarch butterflies mated in the oak trees, distracted not at all by a couple of exuberant and loud acorn woodpeckers searching for less-toxic insects.
Two miles east, the Bypass is drier. My companion sleeps atop a mosaic of cracked mud, the arching tules giving her only a little shade. In a low spot in that parched mud she found skeletons, the shells of tiny fairy shrimp that had clustered in the mudflats' last bit of surface water some weeks earlier.
A quarter mile away where I watch the male tricolored, you could almost persuade yourself the landscape isn't quite as dry. It's meadow-colored, stands of tules and bulrushes separated by green grasses. The fact that tules and bulrushes mainly grow out of standing water gives the lie to that appearance. Who would look at the photo here and think it dry except someone who knew tules and bulrushes are "emergent" vegetation?
I have a feeling of wrongness here that doesn't make sense to me at first. Sure, the wetland is drier than usual, but it's not like the undeveloped Delta didn't have seasonal wetlands that dried up, provided habitat that animals relied on in season, then were re-flooded again in winter.
And then I recognize the feeling. I've felt it before. I'd been in the high plains in North Dakota. On a short walk, I had rounded a stand of chokecherry and found a lone bison on the other side, a couple hundred feet off, regarding me with what seemed mild annoyance.
One bison on a plain that should have been full of them. One tricolored blackbird in the marsh that should have been heavy with tricolored blackbirds. Gaining ecological knowledge can be disheartening. You start to see a layer of wrongness laid down atop all the live and pretty things. Sometime it's in what's there, as in the star thistle. Sometimes, as in the missing tricoloreds, that wrongness lies in what's not there.In his book "A Sand County Almanac," biologist Aldo Leopold wrote perhaps one of the most depressing paragraphs to be found in all of nature writing:
I've spent two and a half decades trying not to have that passage come to mind every day.
I try to shake off the feeling. Though phenomenally dry after half a decade of drought, even with some of the state's most destructive invasive plants scratching the hell out of my unprotected shins, despite the tanker truck parked on dirt a quarter mile off leaking intense ammonia fumes, this is a gorgeous spot. In addition to the tricolored blackbird regarding me warily from his bent tule perch, there are hundreds of redwinged blackbirds raising an aerial ruckus. White butterflies flit around the margins of the levee, likely seeking introduced mustard on which to lay their eggs. A mile north, Interstate 80 traffic hums along the Yolo Causeway, the only vantage point from which the vast majority of people who pass this way ever see the Yolo Bypass.
And there's the tricolored male, who sings to me in his nasal voice. Or to be honest, more likely at me.
Conservationists have been trying to address the continuing decline in tricolored blackbird numbers for decades. As blackbirds, the tricolored were exempted from protection under the Migratory Bird Treaty Act as potential pests of crops. In the precise language of the law, tricolored were held to be threats "to ornamental or shade trees, agricultural crops, livestock, or wildlife, or when concentrated in such numbers and manner as to constitute a health hazard or other nuisance."
That exemption was lifted in 1985, and tricoloreds are now fully protected under the Migratory Bird Treaty Act, which essentially means you can't shoot them just because. Boosting the birds' protection was a good move, but it didn't help enough. One of the biggest threats to tricoloreds is their habit of massing in flocks as large as they can assemble to breed. That's especially true since now that the Central Valley no longer holds the immense stands of bulrushes the tricolored used to breed in, the birds seem to have a special fondness for triticale fields as replacement breeding habitat. Triticale, a hybrid grain grown primarily as silage feed for dairy cattle, is generally harvested right when the birds are nesting.
And that, as shown in this video of a 2006 Merced County triticale harvest, can mean tens of thousands of tricolored blackbirds destroyed in one pass of a combine.
There are dairy farmers in the Central Valley who react with just as much horror to that prospect as anyone else, and conservationists and farmers have come up with innovative voluntary programs to encourage delayed triticale harvests in fields occupied by the birds. That gives the tricoloreds a chance to lay their eggs, hatch them out, and raise their young until they leave the nest. A delay of a month is usually all that's necessary.
Both wildlife advocates and farm associations have enthusiastically signed onto these voluntary programs, which is good news. The bad news comes in the form of a pesky detail: tricolored numbers are still dropping despite all that lovely cooperation at the negotiating table. In 2011, with voluntary programs fully available to provide incentives for delayed triticale harvests, more than half the nesting colonies in silage fields were destroyed anyway.As the Center for Biological Diversity's Lisa Belenky and the Wild Nature Institute's Monica Bond put it in late 2014, in a petition to the California Fish and Game Commission to protect the tricolored under the California Endangered Species Act,
Belenky and Bond pointed out that alternative nesting habitat for tricolored blackbirds has been continually reduced, including patches of invasive Himalayan blackberry of which the birds are fond, and that birds that do find nesting habitat are increasingly picked off by cattle egrets and other novel predators. Pesticide use by farmers reduces the biomass of insects the birds feed their young, leading to nesting failures even on protected habitat.
"Because CDFW cannot demonstrate that concrete measures will be implemented immediately to protect critical nesting sites on private lands in the 2015 breeding season under the voluntary and cooperative partnerships," wrote Belenky and Bond, "listing is necessary and establishment of regulatory protective measures to reduce known sources of Tricolored Blackbird mortality."
The California Fish and Game Commission, the body responsible for deciding whether to list species under the California Endangered Species Act, agreed to give the tricolored blackbird emergency provisional listing under the Act in December. The next step was a Commission vote scheduled for June on whether to conduct a status review of the species, a scientific assessment of whether the tricolored merited protection.
At that June 11 meeting, two of the five Fish and Game commissioners were absent. They would likely have cast votes in favor of the status review. Instead, Commission opponents of listing the tricolored prevailed in a 2-1 vote. Those Commissioners cited the voluntary programs as sufficient reason not to protect the birds, despite the continued decline in tricolored numbers.
To borrow Leopold's words, those pro-ag commissioners and their trade group constituency were a good example of a "community that believes itself well and does not want to be told otherwise." And so they disregarded their doctors' advice.
Ten days after the Commission vote, my shins itching from scratches inflicted by the star thistle's fiendish spines, I watch that lone tricolored on its bent tule. And it watches me. I linger. It's five minutes past the time I'd told my companion I'd roust her from her bed of tules, but I don't know when I'll have a chance like this again.
And then I do turn to leave, and the tricolored decides to come with me, flying ahead of me and landing a few yards up as I walk, or hovering long enough for eye contact. I have no idea why. Am I a threat? It is just curious? I'm reluctant to anthropomorphize, but I just don't know.
Nor do I know whether it's something in the bird's behavior, or solely something I bring to the moment entirely in my own mind, that says over and over again, "Remember this. Remember this."
Against the sad chance that I will not have another experience like this one, I will.
For ongoing environmental coverage in March 2017 and afterward, please visit our show Earth Focus, or browse Redefine for historic material.
KCET's award-winning environment news project Redefine ran from July 2012 through February 2017.
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