recorded - The Environment Report

Recording Elephant Conversations

Elephants talk amongst themselves below levels we can hear. (Photo courtesy of the Elephant Listening Project in Dzanga National Park)
An image of a series of elephant calls. Researchers are using these calls to count how many elephants are in the wild. (Photo courtesy of the Elephant Listening Project in Dzanga National Park)
Project headquarters - the Cornell Lab of Ornithology. (Photo by Emma Jacobs)

Biologists are always trying to
get a good count of the animals
they’re studying. You wouldn’t
think it’d be that hard to find
an elephant for a count, but even
some of the largest animals are
difficult to count in the wild.
So researchers are now trying new
methods. Emma Jacobs reports on
a Cornell University project which
is using audio recordings to learn
more about elephants:

Transcript

Mya Thompsons sits down in her lab and pulls up a set of recordings on her computer. She helped tape these sounds for the Elephant Listening Project in Dzanga National Park in the Central African Republic. She plays a recording made in the forest, late at night.

(sounds of the forest at night)

“You heard some insects, you heard some sort of the din of a nighttime forest.”

But you probably don’t hear elephants.

Next, Thompson takes the same sound and speeds it up on her computer. Suddenly, you can hear something else.
“This is 4-times normal speed.”

(sound of forest at night, but with rumbles)

Elephants make those low rumbles. When she speeds up the playback, they rise in pitch. It’s kinda of like the voices of Alvin and the Chipmunks.

It turns out elephants talk among themselves below levels we can hear. Biologist Kaity Paine discovered these sounds in the 1980s. She realized that because elephant rumbles are so low, they travel long distances. This should make them useful to track elephants over wide forests, but Thompson remembers that in the field, it was hard to see how.

“We’re collecting all this information and we wanted to know what the calls were like, but because we can’t hear them, we were almost totally in the dark about what was going on.”

When she got back to New York, Thompson and the rest of the research team started combing through all the audio and video collected in Central Africa for elephant calls. It took thousands of hours.

But with time, they could nail down a pattern. The key was a relationship between the audio recordings and the video of elephants they had made in one clearing popular with elephants.

“This is a communication system. There are a lot of other variables other than, ‘Hi I’m here,’ but, overall, the more calling, the more elephants and that was good news for us.”

Now Thompson can monitor elephants over huge areas of this dense forest using these audio recordings.

In the field, the team hoists their recorders into trees attached to truck batteries. They can stay up there a long time, which has real advantages.

“Usually, when you take a survey, you go, you count, and you leave. For acoustics, we’re able to have this recorder up continuously without all this human effort and make repeated estimates over longer periods of time.”

With enough information, Thompson can estimate at the numbers of elephants in a forest with twice the precision she could have before.

Marcella Kelly teaches wildlife field techniques at Virginia Tech. She says, when you can track animal numbers closely, you can see how they respond to changes in their environment. This is a must for conservation.

“We really need effective ways to estimate population size, especially because decisions are made on management based on what those numbers tell us, over time.”

The Elephant Listening Project recently started monitoring elephants in the African nation of Gabon.

“The authorities had allowed gas exploration to see if there’s any petroleum reserves there, and so our project was asked to monitor the forest for elephant calls before, during, and after this exploration.”

Thompson can already say that things have changed. Elephants have started coming out more at night than during the day to avoid people. In the end, hopefully she’ll be able to see just how disruptive changes have been and to pinpoint the human activities causing problems.

She also wants to protect other animals making noise in the forest, and outside it.

“We’re really hoping that these methods that we’ve developed, will be developed for not only forest elephants but for other species that are hard to survey that we really need to know more about before we can protect them.”

For right now though, Thompson is still in her lab, listening for elephants.

For The Environment Report, I’m Emma Jacob

Big Apple Tree-Huggers

One NYC artist recruited arborists and neighbors to record messages about the city's trees. She placed markers in the cement listing numbers to call to hear the recordings. (Photo by Samara Freemark)

Trees along big city streets have a rough
life. Between pollution, development,
and vandalism, street trees die off at
a pretty alarming rate. One New York
artist thinks if people knew more about
street trees, they’d appreciate them more –
and treat them better. Samara Freemark reports from New York’s “Tree
Museum”:

Transcript

When artist Katie Holten was commissioned to do a piece commemorating Grand Concourse boulevard in the Bronx, the first thing she thought of was trees. The Concourse, after all, is lined with them. The problem was, no one else seemed to notice they were even there.

“I had conversations with people who were sitting under the trees for the shade. And I’d ask them about what they thought of the trees. And they would say, ‘oh, there aren’t any trees on the concourse.’ But they were sitting underneath one.”

And if people did notice the trees, they weren’t always thrilled they were there.

“Kids told me that trees should all be chopped down because they couldn’t see the view. A teacher told me that all trees were the same, that there was only one kind of tree.”

People didn’t pay much attention to the trees. When they did, they often abused them – which is pretty common treatment for the trees that line city streets. People pin street trees with flyers. They spray trees with grafitti. They chain their bikes around trees, stripping their bark. City buses jump curbs and plow into trees. And developers chop them down to put up new buildings.

“You can’t just stick a tree in the ground and hope for the best. It’s a really tough environment.”

In fact, half of all trees planted in New York City die.

Holten figured one way to protect street trees was to get people to understand all the good that trees do.

So she recruited arborists and neighbors to record messages about the Grand Concourse’s trees. She placed markers in the cement listing numbers to call to hear the recordings. And she called the whole thing the Tree Museum.

“There are 100 trees along the 4 miles. And each of the trees gets a small marker. So we can walk up here to 165th street and I’ll show you one. Here’s one of the markers- nice and dirty.”

(sound of dialing in)

We dial and hear…

“I’d like to a moment to say thank you to this tree. This tree is busy cooling the air and helping to keep the river clean. The leaves in the canopy above are pulling water out of the air, reducing humidity, like an AC.”

It’s not really clear how many people are actually calling in to the museum, or whether the recordings are changing anyone’s mind. But it’s a start.

Joyce Hoagy lives further up the Concourse. She recorded a message for tree number 31. And now she feels kind of possessive of it.

“This is my tree. It’s a honey locust and I’m identified by it.”

Hoagy says Bronx trees have been under particular threat lately. This year the city cut down hundreds of mature oaks to make room for the new Yankees stadium.

“One street had these giant oaks, and they formed this canopy. And on the hottest day of the year you could walk down…people didn’t know what they had till it was gone.”

So now Joyce Hoagy’s spreading the word about the Tree Museum too. She hopes it will give her neighbors a hundred reasons to care about trees around them – and watch out for them.

For The Environment Report, I’m Samara Freemark.

Rare Right Whale Recorded

Only two Right Whales have been spotted in the last 50 years off the southern tip of Greenland (Photo courtesy of NOAA)

Scientist think they’ve found
a rare whale in a place where
they thought they were wiped
out. Sadie Babits reports,
they haven’t seen the whale
but they’ve heard it:

Transcript

Scientist think they’ve found
a rare whale in a place where
they thought they were wiped
out. Sadie Babits reports,
they haven’t seen the whale
but they’ve heard it:

Scientists thought the North Atlantic Right Whale
was gone. Only two of them have been spotted in
the last 50 years off the southern tip of Greenland.

But some underwater microphones picked up right
whale calls.

“They sound like mmmmmmick… kind of like that.”

That’s David Mellinger. He teaches at Oregon State
University.

He says they recorded more than two
thousand right whale calls in a year. That doesn’t
mean there are a lot of the whales, but Mellinger
says hearing any in the North Atlantic is significant.

“Because the population is so endangered. There
are only 300-350 maybe right whales in the world.
So finding any new whales is important.”

But there is a concern. As the Arctic Ice Cap
melts because of global warming, more ships are
expected to pass through the area. That could
mean ships could strike and kill the few right
whales that are left.

For The Environment Report, I’m Sadie Babits.

Tag: recorded

Big Apple Tree-Huggers

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Rare Right Whale Recorded

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