MICHELE NORRIS, host:
This is ALL THINGS CONSIDERED from NPR News. I'm Michele Norris.
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And I'm Melissa Block.
The U.S. Interior Department and conservation groups today released a report on the overall state of the nation's bird population.
It includes some good news but warns that many of the 800 bird species in the U.S. are in trouble. NPR's Elizabeth Shogren went in search of one increasingly rare bird.
ELIZABETH SHOGREN: David Ziolkowski says, when he first started birding 20 years ago, he saw lots of rusty blackbirds.
Mr. DAVID ZIOLKOWSKI (Biologist, United States Geological Survey): I can remember seeing flocks of hundreds of them, kicking out of the wetlands and out of the flooded forest.
SHOGREN: Now they're very rare, but they just happen to be migrating through here, the Patuxent Wildlife Research Center in Maryland.
Mr. ZIOLKOWSKI: I can use a little bit of song, and sometimes that'll bring a flock in. Their song kind of sounds like a rusty hinge that you might expect on a farm door somewhere out in Kansas.
(Soundbite of bird call)
SHOGREN: That's a recording he plays to lure them closer. Ziolkowski works for the U.S. Geological Survey. One study he works on provided key data for the new report.
Mr. ZIOLKOWSKI: The rusty blackbird is a great example of what the State of the Birds Report is really trying to get at. Somewhere between 75 percent and 90 percent of its population has been lost within the last 40 years.
SHOGREN: Do you know why the rusty blackbird has declined so much?
Mr. ZIOLKOWSKI: Well, 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.
SHOGREN: The birds don't answer Ziolkowski's call, so we move on to a flooded forest, where he often sees them.
Mr. ZIOLKOWSKI: One thing that'll oftentimes make them jump up is if you give a barn owl song.
(Soundbite of owl call)
SHOGREN: No luck, but some other birds pass overhead.
Mr. ZIOLKOWSKI: Those are wood ducks that just flew by.
SHOGREN: Ziolkowski says wood ducks are a great example of how people can save endangered birds. They've done it by restoring habitats and by banning pesticides like DDT. That helped many birds rebound, including the bald eagle.
At least, Ziolkowski spots a small flock of rusty blackbirds in a tree. They swoop down into the muddy wetland.
Mr. ZIOLKOWSKI: And you can see, even from here with the naked eye, that the males are all very dark-colored, sort of this velvety black, and the female is lighter grey. She's towards the back edge of the flock.
SHOGREN: We hear the calls of lots of other birds but still not a peep from the rusty blackbirds.
Mr. ZIOLKOWSKI: They just don't seem interested in singing right now.
SHOGREN: Ziolkowski says we're fortunate even to see them. Future generations might not have that chance. Today's State of the Birds Report shows lots of other birds are in trouble.
Half of the birds that migrate along the coasts are declining. So are many sea birds 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 other place.
Mr. ERIC VANDERWORTH(ph) (Bird Expert): Unfortunately, a lot of the richness is under threat right now.
SHOGREN: Eric Vanderworth is an expert in Hawaiian birds.
Mr. VANDERWORTH: 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 of decades.
SHOGREN: Like the Oahu elepaio.
Mr. VANDERWORTH: 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.
SHOGREN: He says Hawaiian birds evolved without risks like rats and disease-carrying mosquitoes. To save them, people will have to come up with inventive ways to reduce those threats. Elizabeth Shogren, NPR News.