Tag: migrate

Birders Flock to Hawk Mountain

Each fall, thousands of hawks, eagles, and other birds of prey fly hundreds of miles in search of warmer climates. And between August and December, nearly 70-thousand people will climb to the top of a bird sanctuary called Hawk Mountain to get a closer look at those birds. The Great Lakes Radio Consortium’s Brad Linder reports:

Transcript

Each fall, about thousands of hawks, eagles, and other birds of prey fly hundreds of miles
in search of warmer climates. And between August and December, nearly 70-thousand
people will climb to the top of a bird sanctuary called Hawk Mountain to get a closer
look at those birds. The Great Lakes Radio Consortium’s Brad Linder reports:


“Those of you haven’t found the osprey, it’s over there at owl’s head, naked eye here to
the right.”


On a clear day, the view from atop Hawk Mountain stretches for more than fifty miles.
But on this particularly hazy Saturday afternoon, bird-watchers are pushing their
binoculars and telescopes to the limits.


“Well, we’re making them out there, they’re coming in. It’s like you just gotta wait ’til
they get a little closer than what they typically do. They’ve been popping out of clouds
and haze all day for us.”


Doug Wood is a volunteer at Hawk Mountain in Eastern Pennsylvania. This afternoon,
he’s the official bird counter.


“We’re basically taking a lot of field information. Wind, weather, temperature, cloud
cover, wind direction. And then we’re basically monitoring the birds’ species, age, sex,
and recording it every hour.


“Look! An Osprey! And then fade to scene change.”


Researchers at Hawk Mountain have been keeping records of osprey and other migratory
raptors for more than seventy years, making it the oldest monitoring station in the world.


In the early twentieth century, hunters would shoot thousands of birds from the
mountainside each year. Today, people travel from all over the world to shoot birds with
their cameras.


Matt Wong came all the way from New Zealand to study at the sanctuary.


“Hawk Mountain is internationally renowned as a hawk watch site. And also a place
where big research actually happens. Now, not many of the locals around Pennsylvania
actually realize this, but it’s actually huge on the international scene. It’s world
recognized, and that’s one of the reasons why I came here.”


In Wong’s country, there are only two species of raptors. In America, he’s had a chance
to study dozens of varieties.


But even with so many different species populating North America, many people still
think of them as strangers or sometimes even as monsters.


“I still get, amazingly to me, a lot of people that think that these birds are out to get us.”


Volunteer Bob Owens has spent the last 20 years doing education programs at Hawk
Mountain.


“If you intrude into their territory when they have young in the nest, or something like
that, yeah, they’re probably going to chase you. As far as them killing babies and taking
them from baby carriages, this is all old wives tales. This just does not happen.”


Owens runs a small farm for a living, where he says hawks and barn owls help keep
rodents under control. But in a larger sense, Owens says there’s a lot people can learn
from these birds.


“Any three and a half pound bird that can apply four hundred pounds of pressure with its
talons is built to do what they’re doing. They are at the top of the food chain. And that’s
the other big thing that it shows us. It just opens up a door here as to all the reasons the
birds are either dropping or rising in population. What are we doing?”


Owens says in the seventy years researchers at Hawk Mountain have been counting birds,
they’ve seen populations rise and fall. Hawks and eagles are hardy birds. But even the
most successful predators can fall victim to environmental change.


Keith Bildstein is the sanctuary’s director of conservation programs. He says raptors are
like sensitive tools, telling researchers when something’s wrong with an ecosystem.


“Birds of prey are excellent biological indicators. In the middle of the last century they
told us that we were having a problem with our misuse of organochlorine pesticides,
specifically DDT. Today, they’re leading us in explorations of the spread of West Nile
Virus.”


Bildstein says because raptors are at the top of the food chain, when their numbers fall
it’s a pretty good sign that their food source is dwindling, their habitat could be
disappearing, or air quality might be suffering.


But for most of Hawk Mountain’s visitors, the birds are more than barometers of a
healthy ecosystem. According to birder Judy Higgs, they’re beautiful creatures,
especially when viewed from a great height.


“These birds are just majestic. And the other thing is that they go so far. You know,
some of these birds are going to South America!”


Higgs first climbed the mountain in 1970, when she was a student at nearby Kutztown
University. Before moving out of state, Higgs used to come to Hawk Mountain daily…
she stills visits on weekends whenever she can.


“I used to do work in the morning, come here in the afternoon, go home, and finish my
work at night so I could be here.”


By day’s end, Higgs and her fellow birdwatchers count more than 600 raptors. During
the fall season, as many as 70-thousand predatory birds, from vultures to falcons might
pass by on their way to distant points.


For the Great Lakes Radio Consortium, I’m Brad Linder.

Unraveling Mystery of Birds’ Night Calls

  • Ornithologist Bill Evans has been tracking down avian night flight calls for 17 years.

Many North American birds are in serious decline. But scientists aren’t sure what’s wrong because birds are hard to count. The problem is partly that birds often migrate long distances between wintering sites and summer breeding grounds. Usually, they fly unobserved at night, and in many cases scientists don’t know what route they take. However, a new technique promises to solve this problem. The Great Lakes Radio Consortium’s Daniel Grossman has our story:

Transcript

Many North American birds are in serious decline. But scientists aren’t sure what’s wrong because birds are hard to count. The problem is partly that birds often migrate long distances between wintering sites and summer breeding grounds. Usually, they fly unobserved at night, and in many cases scientists don’t know what route they take. However, a new technique promises to solve this problem. The Great Lakes Radio Consortium’s Daniel Grossman has our story:

(Sound on dock, with Evan’s whispering out bird names fades up under intro.
Continues under Grossman track, then heard in clear.)

It’s a warm spring evening on the south Texas coast. Ornithologist Bill Evans sits on a dock, listening for birds.

“Grey-cheek thrush.”

Grossman: “That high one?”

“Yeah. (makes sound). Moor hen calling behind us on the ground. Oh sorry, that’s a black-necked stilt.”

Evans has been listening to and studying these night calls since he had an epiphany at a Minnesota campground in 1985. Then a recent college dropout and avid birder, Evans was adrift, unsure what to do with his life.

“I was getting back to a campsite about two in the morning and heard an incredible flight.”

Hundreds of birds were passing overhead in nocturnal migration, including what appeared to be about 100 black-billed cuckoos.

“If you go out and look for black-billed cuckoos during the day you may see two or three. And I’m thinking, ‘wow if I had a tape recorder and could somehow document this on audiotape, I might have a pretty powerful conservation document.'”

Bill Evans got a recorder and soon was making tapes of flight calls. But his recordings were of limited use because no one knew which birds made which sounds. The melodious tunes birds perform during the day are well known. But, according to Cornell Professor Charles Walcott, the calls they make during night flights are another matter.

“If you out on an evening and listen to these birds migrating overhead you’ll hear all these twitters, most of which don’t sound anything like what a normal bird sounds like at all.”

Walcott is the former director of the Cornell Ornithology Laboratory. He says night calls may help birds keep from colliding with each other. For decades, researchers hearing these calls were frustrated knowing there were birds in flight, but unable to determine which ones.

“And to be able to recognize individual species by their calls was a dream that many people have had. And Bill is the first one that’s been able to do it on any substantial scale.”

Evans spent the next 17 years prowling migration routes to match birds with their calls. Often his only chance came in the wee morning hours, when sometimes night migrants make a single night call before settling down to eat and rest. Gradually he cracked the code.

“The herons. Amazing squawks. Black-crowned-night heron is a sort of (makes sound). Green heron is a (makes sound). Barn owl. It’s a [makes sound]. Except it’s about ten times louder than that. The dickcissel is actually a sparrow and it’s got sort of a buzzy note (makes sound).

(Sound of truck door closing and truck starting up)

The small, colorful dickcissel is why Bill Evans is here, just north of Brownsville, Texas. He’s set up a network of 15 computerized monitoring stations that listen for dickcissels in flight. It’s the first large-scale effort to track birds using night calls. The network is stretched out along a line he believes these birds cross on their way between Venezuela and the U.S. plains.

Each station has a roof-mounted microphone, connected to a computer. Most of them are at high schools – their large, flat roofs and spacious grounds reduce traffic noise – and they’re generally in a science class. And while Evans does stay up late to listen for pleasure, it’s these computers that are actually doing the work. Each day he collects the past night’s results, in a marathon drive, station by station.

(Sound of high school PA System making announcement cross fades with truck under previous track. Also mixed in sound of crowded high school corridor with students changing classes. Cross-fades with sound of classroom.)

Evans: “Come on over guys. My name is Bill, this is Dan.”

Peter: “Bill and Dan?”

Evans: “What’s your name?”

Tate: “Tate.”

Peter: “Peter.”

Bill: “Nice to meet you guys.”

Some curious students pay Evans a visit at La Ferria High School.

(Evans fades up underneath Grossman. Then heard in clear.)

Evans (to students): “…So anyway the sound comes down this audio cable into this computer. We’re just checking the data from last night…”

(Computer keyboard sounds in actuality fades under track.)

The computer has a program that distinguishes the call of the dickcissel from other birdcalls and extraneous noise. The machine records the call, and saves a picture – or spectrogram – of it. Evans trouble shoots his stations and collects data daily. First he winnows out false positives, sounds that tricked the computer, by inspecting the spectrograms.

Evans (to students): “I’m going to set up one folder to put in the dickcissels’ calls and the other I’m going to put in the noise, the false detections. So now I’ve just classified the detections from last night. We had 28 here that we classified as dickcissels…”

After checking the computer and collecting its data the researcher says he has to run. Each of the 15 stations in his network needs a checkup because this weekend might be the climax of the dickcissel migration, bringing a huge flight of birds.

Evans (to students): “…And this weekend we think there are thousands of them just in Northeast Mexico. They’re going to take off. ‘Cause last year in one night, we had over 3,000 detected at McAllen High School…”

In the end, the big flock didn’t appear until the following week. Though the arrival was delayed for several days compared to the previous year, Evans now has proof that by monitoring night calls he can predict the timing and migration route of an individual bird species.

(Sound of truck door closing and truck starting up.)

Walcott: “It’s really an extraordinary accomplishment.”

Cornell professor Charles Walcott says the migration information Evans is discovering can’t be collected any other way. It’s all the more extraordinary because Bill Evans, who once worked for Walcott, has neither a college nor any other degree.

Walcott: “With Bill’s scheme you can now say, well, this was an evening when we had a huge migration of warblers and they were of the following species. And this is very useful and very interesting information. And it gives you a sense of where the migratory paths for each species of birds might be.”

It’s detailed information like this that conservation specialists need to design plans to protect the most threatened species. In the future Evans hopes several large-scale computer networks of the sort he’s testing in Texas will monitor many species throughout the United States. He hopes the listening posts could help solve the mystery of why so many North American species are in decline. This spring, in an important first step, Evans and collaborator Michael O’Brien released a compact disc with night flight calls of most eastern land birds. Now anyone can learn the secrets Bill Evans has unlocked.

For the Great Lakes Radio Consortium, this is Daniel Grossman.

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Whoopers Prepare for Historic Flight

Ten whooping crane chicks that may go on a historic flight through part of the Midwest this fall are about to start flying lessons. The Great Lakes Radio Consortium’s Chuck Quirmbach reports:

Transcript

Ten whooping crane chicks that may go on a historic flight through part of the Midwest this fall are about to start flying lessons. The Great Lakes Radio Consortium’s Chuck Quirmbach reports.


Public and private sector wildlife experts are trying to set up the first migrating flock of whooping cranes in the Eastern U.S. the plan is to have the birds learn their migration route this October by following ultra-light aircraft from Wisconsin to Florida. Ten two-month old whooping crane chicks have just finished the first step of the experiment at a federal wildlife center in Maryland. Joan Guilfoyle of the u-s fish and wildlife service says the chicks went through ground school.


“Right from coming out of the egg they were exposed to sounds of ultra light engines, being able to see people in costumes disguised as adult whoopers, so they would begin to associate their care and protection with those two things.”


Now the crane chicks have been brought by private plane to
Wisconsin, where ultra light pilots wearing crane costumes will give the birds flying lessons. Many of the same people worked on a test migration with smaller but more plentiful sandhill cranes last year. Guilfoyle says there are some behavioral differences between sandhills and whoopers.


“One of them is sandhills tend to migrate in groups more than whoopers…so we will learn the right number to group…may be all ten of them together or they may end up in two groups.”


A century ago, it’s believed about one thousand whooping cranes roamed parts of North America. Today, the species is endangered. The only remaining migrating flock of whoopers numbers about one hundred and seventy five. That flock spends its summers in Canada, before heading to Texas for the winter. If the human-assisted migration in Wisconsin is successful this fall, scientists hope to continue the reintroduction. And they say they could have as many as 25 breeding pairs of whooping cranes living in the Wisconsin to Florida flock within the next ten years.” For the Great Lakes Radio Consortium, this is Chuck Quirmbach in Milwaukee.

Problem Geese Headed for Soup Kitchens

Canadian geese can easily be found alongside roadways or in suburban
neighborhoods at numbers far greater than a decade ago. Each year
millions of the birds migrate north through the Mississippi Fly-Way
settling in the Great Lakes region, leaving states grappling with ways
to control hordes of geese. In Ohio, a new plan is underway to use
so-called problem geese as food for soup kitchens. The Great Lakes
Radio Consortium’s Natalie Walston reports: