Grassland birds like this Eastern meadowlark have declined in part because of increased agriculture.
Grassland birds like this Eastern meadowlark have declined in part because of increased agriculture. iStockphoto.com
David Ziolkowski of the U.S. Geological Survey walks through the Patuxent Wildlife Research Center in Maryland. His survey helped provide the information for the state of the birds report.
David Ziolkowski of the U.S. Geological Survey walks through the Patuxent Wildlife Research Center in Maryland. His survey helped provide the information for the state of the birds report. Elizabeth Shogren/NPR
U.S. Fish and Wildlife Service
Rusty blackbirds used to be common, but the species has been in decline since losing habitat.
This common moorhen lives in marshes and can take advantage of small, changing wetlands, which has helped its population remain stable over the past 40 years.
When David Ziolkowski first started birding 20 years ago, he saw lots of rusty blackbirds.
"I can remember seeing flocks of hundreds of them kicking out of the wetlands and out of the flooded forests," says Ziolkowski, a biologist for the U.S. Geological Survey.
Now the birds are so rare that they were highlighted as a bird in trouble in the "State of the Birds" report released by the U.S. Interior Department, the Cornell Lab of Ornithology and several conservation groups. The report warns that scores of the 800 U.S. bird species are declining.
"The rusty blackbird is a great example of what the 'State of the Birds' is really trying to get at. Somewhere between 75 and 90 percent of population has been lost within the last 40 years," says Ziolkowski. "The biggest factor is probably loss of wetland habitat. Most populations of birds are really declining now primarily because of rampant development and urban sprawl."
The report includes some good news about birds that were on the brink of extinction but have rebounded because of conservation efforts, including the Laysan duck and the wild turkey. But it also says many bird species are in trouble — including birds that live on the oceans, in grasslands, in deserts, in the Arctic, on the coasts, in wetlands and in forests.
Development, agriculture, energy production, pollution, invasive species and climate change all put birds at risk.
As it happens, rusty blackbirds migrate through Maryland this time of year, and Ziolkowski hopes to find some of the rare birds at the Patuxent Wildlife Research Center, where he works.
"I can use a little bit of song, and sometimes that will bring a flock in," Ziolkowski says as he plays a recording to lure the birds closer. "Their song sounds like a rusty hinge that you might expect on a farm door somewhere out in Kansas."
The birds don't answer, so Ziolkowski moves on to a flooded forest where he often sees them. Instead, a couple of wood ducks fly past.
Ziolkowski says wood ducks are a great example of how people can and do save endangered birds. They have done it by restoring and protecting habitats, and by banning pesticides like DDT, which helped many birds come back, including the bald eagle.
At last, Ziolkowski spots a small flock of rusty black birds in a tree. They swoop down into the muddy wetland.
"You can see even here with the naked eye that the males are all very dark colored, sort of this velvety black, and the female is lighter gray," he says.
But the birds don't make a peep.
Ziolkowski says it's fortunate even to see them; future generations might not have that chance.
The report shows that many other birds are in trouble. Half of the birds that migrate along on the coasts are declining, and so are many seabirds and lots of the birds that live in grasslands and in deserts.
And despite Hawaii's reputation for rich flora and fauna, more bird species are vulnerable to extinction there than any place else.
"Unfortunately, a lot of the richness is under threat right now," says Eric VanderWerf, an independent expert in Hawaiian birds. "We've lost several species of forest birds in the recent past, and there are several more that we easily could lose in the next couple decades."
One at risk is the Oahu elepaio.
"Rats will climb up a tree in which elepaio are nesting and eat the eggs, and if they can, they'll catch the female and eat her, too," VanderWerf says.
Hawaiian birds evolved without risks like rats and disease-carrying mosquitoes, and to save them people will have to come up with inventive ways to reduce those threats, he says.