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PRI's Environmental News Magazine

Grassland Birds

Air Date: Week of July 24, 1998

How often do you see open stretches of grassy fields? Probably not very frequently. That's because grasslands are becoming more and more endangered in this country. That means more than the loss of plant life. The birds which make their homes in the grasslands are finding fewer and fewer places to go. Some call the loss of these birds "America's most neglected conservation problem." Brenda Tremblay of member station WXXI has the story.

Transcript

CURWOOD: It's Living on Earth. I'm Steve Curwood. The next time you're driving down the road, look around for some open stretches of grassy fields. You may not see many. Grasslands are disappearing from Maine to California, and because the fields are vanishing, so are the birds that live in them. Brenda Tremblay of member station WXXI in Rochester, New York, has looked at what some call America's most neglected conservation problem. She reports on the recent sharp decline of grassland birds and the debate about what can be done to restore the shrinking populations.

(Bird song and footfalls)

TREMBLAY: Since birds get up with the sun, so does biology graduate student Carla Balent. Every morning she wakes up before dawn to drive to a field outside of Rochester, New York. It's a green and gold meadow dotted with wild blackberries, honeysuckle, milkweed, and grasses. Sunlight glints off the dew-covered spiderwebs spun between tall stalks of goldenrod.

BALENT: Most people drive by and say, "What a great place for a house!"

TREMBLAY: Carla Balent comes here to look for a certain kind of bird called a grasshopper sparrow. She's collecting data for a study of these birds and their nesting habits. To attract them, she pulls out a tape recorder and plays the sparrow's chirp through a loudspeaker.

(Chirp through loudspeaker)

BALENT: Is that him?

WOMAN: Yeah, he came out from the woods.

BALENT: Yeah, that's where we flushed him last time.

(Chirp through loudspeaker continues)

TREMBLAY: After she spots one brown, streaky sparrow, she sets up a fine net and crouches in the grass nearby, waiting for the bird to fly into it. Instead, this sparrow keeps flying over the net. Carla Balent grimaces and eventually gives up hope of catching the bird to stick a band on its leg.

BALENT: Come on. This bird is very crafty. I think this is the same one we tried to catch one morning, and he flew over the net so many times it wasn't funny.

(A long chirp)

TREMBLAY: It's getting harder and harder to find grasshopper sparrows. Since the 1960s, their population has plummeted by 96% in New York State. And throughout the country, the bird's population is only a third of what it used to be. And other grassland birds are disappearing, too: eastern meadowlarks, bobolinks, and the quirky little Henslow sparrow with its odd song. According to Dr. Robert Askins, a zoologist at Connecticut College, 15 of the 19 species of America's grassland birds have declined since 1966.

ASKINS: So a lot of these birds are in severe trouble, and we're in danger of at least losing them from major regions of eastern North America. And eventually some could be in danger of extinction throughout the world.

TREMBLAY: There are plenty of reasons for the decline, and there's plenty of debate about when in US history grassland bird populations were best balanced with their surroundings. In the east, the story starts with the arrival of European settlers. Back then, folklore says, a squirrel could have hopped from tree to tree all the way from the Atlantic coast to the Mississippi River. Though that may be a slight exaggeration, the forest shrank dramatically when settlers began to cut down the trees and clear fields for farming. And that's when grassland birds began to thrive. While forest birds like the wood thrush found fewer and fewer trees to nest in, grassland birds like the bobolink found more and more good habitat in the fields and pastures of 19th century America. By the middle of the 1800s, grassland birds were widespread. Even poet Emily Dickinson wrote about the bobolink that sang in her garden in Amherst, Massachusetts.

(Birds chirping)

WOMAN: (Reading Dickinson)

Some keep the Sabbath going to church --
I keep it staying at home --
With a bobolink for a chorister --
And an orchard for a dome.
Some keep the Sabbath in surplus --
I just wear my wings --
And instead of tolling the bell for church
Our little sexton sings.

(Mechanical sounds)

TREMBLAY: Then around the turn of the century, the landscape in the east began to change again. Cities and towns expanded into the surrounding countryside. As small farms began to decline, trees started to reclaim the land. Hunters killed the birds for sport. Dr. Robert Askins says the first grassland bird to feel the effects of the changes was the heath hen.

(Heath hen calls)

ASKINS: The heath hen was a subspecies of the greater prairie chicken, a species that's still found on the Great Plains. Unfortunately, the heath hen became extinct in the 1930s. The last relic population was on Martha's Vineyard, where valiant efforts were made to save it. But it eventually became extinct.

(Calls continue; fade to bird song and waving grasses)

TREMBLAY: What's happening to grassland birds in the East is also happening to them in the Midwest. But in the Midwest, more aggressive agricultural development is to blame. Dr. Jim Herkert works for the Illinois Endangered Species Board. He's an expert on grassland birds. He says the Midwest used to be covered with natural prairies. When 19th century settlers dug up the prairies for farms, the birds adapted pretty well. The problems for grassland birds, Dr. Herkert says, started here after World War II, when farmers stopped letting their fields and pastures remain fallow. They wanted to grow a new crop: soybeans. And growing soybeans required intense row cropping that's unwelcoming to birds.

HERKERT: Now, that's about a 10-million acre crop in the state here, and the kind of fields that came out to put in the soybeans were the pastures and the hay fields. We've seen almost a 50% drop in acreage, millions of acres lost. We know the birds were in there and so it's not really too surprising, perhaps, that some have declined.

TREMBLAY: In response, wildlife managers in the Midwest have begun to look for ways to recreate habitats. In Illinois, biologists are establishing a vast, new tall grass prairie near Chicago. The US Fish and Wildlife Service is planning a national wildlife refuge covering 70,000 acres of prairie across Iowa and Minnesota.

(A car honks. An engine starts up.)

TREMBLAY: Even in the East, wildlife managers have decided to try to hold onto the few small grasslands that remain here. At the Montezuma National Wildlife Refuge in central New York State, biologist Tracy Gingrich oversees an elaborate effort to maintain fields that will appeal to birds like the grasshopper sparrow. He mows 500 acres every couple of months and he has to mow in synch with the bird's nesting habits.

GINGRICH: And that's similar to what a homeowner would do when they're mowing the grass on their lawn, is that you're trying to encourage the grasses and discourage weeds, like dandelions or plantain in his lawn. And by mowing it you stress those plants so they're not as able to compete as well with the grasses that are adapted to frequent mowing.

TREMBLAY: After he mows, Mr. Gingrich applies pesticides to kill certain shrubs and weeds. Next spring he'll burn these fields to simulate a natural brush fire. He says it costs about $75 per acre per year to maintain the fields at this refuge. And by doing all of this, Mr. Gingrich is deliberately preventing this field from reverting to what was probably its natural state, a forest. And that's where some scientists are questioning the point of preserving open grasslands in the East. Dr. Robert Askins says 80% of Connecticut used to be farm land. Now much of the state is covered with trees.

ASKINS: To a certain extent it is not a cause for concern, because the return of the forest brings us back to a landscape more like what the first European settlers saw in the 1500s and 1600s.

TREMBLAY: But Dr. Askins is afraid that we've allowed the forest to reclaim too much grassland.

TREMBLAY: And we're in danger of ending up with a very monotonous landscape that's characterized by a young forest or development, without any of the tremendous diversity of habitats that once characterized the area.

TREMBLAY: Scientists are at odds. They want to maintain diversity, but their inability to agree on a goal or a historical benchmark for the birds' population has slowed the effort to protect the birds' habitat. Still, some plans are going forward. Congress has renewed the Crop Land Reserve Program, which helps farmers maintain empty fields for nesting birds. And biologists working for the Federal Breeding Bird Survey are watching the birds closely. Dr. Jim Herkert of the Illinois Endangered Species Board is troubled, he says, because scientists don't really understand what the repercussions of a drop in the birds' population might be on the larger ecosystem. That's why he thinks it's important to hang onto the meadows and prairies that still exist today. It'll serve as a template for the future.

HERKERT: In several of the eastern states we've got so little left. We've got, you know, much less than 1% of the native prairie, a habitat that in Illinois covered 21 million acres. We've got only a few thousand acres of high-quality stuff left. So it's really important to maintain that, just as a sort of a template as we get into restoration, and so that we can use them as guides for our prairie restorations.

(Bird song)

TREMBLAY: A grasshopper sparrow makes a short, sputtery flight from a low shrub to a mullen plant in a field in upstate New York. Most of the people driving by this field probably don't even notice the little brown bird. But a few years down the road, this sparrow and its companions may be far more conspicuous by their absence. For Living on Earth, I'm Brenda Tremblay in Rochester, New York.

 

 

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