Revealing the secret life of birds

A barn owl lies on Motti Charter's lap, a cloth bag over its head, its feet tied up with rope.

The brown-white bird is visibly, terribly scared. But it lies very still as the researcher fiddles with straps to adjust a black metal device on its back.

The device is about two centimeters long and equipped with a 20 centimeter antenna.

Researchers from the Hebrew University of Jerusalem and Tel Aviv University developed the new tracking device which they hope will revolutionize avian behavior research.

"This tag provides data every two seconds, which is amazing!" Charter tells DW.

Once Charter lets the barn owl go, the tag transmits radio signals. They are received by seven ground stations based around the area, which calculate the owl's location.

Researchers can see in real time where the bird flies - around the clock.

"You can even see the barn owl flying at night time," Charter enthuses.

"Each tag lasts for about four months," says the bird researcher. "And the amount of data you get is almost too much."

Big bird data

"Ten years ago, when Motto Charter was doing his PhD, he was lucky to get a couple of hundred data points per project," says Ran Nathan, professor for movement ecology and co-developer of the tracking system.

"Now we get these data points in less than an hour," says Nathan. "We can address questions like interaction between male and female birds, where the fledglings go when they leave their nests, and how they establish their own territory."

Ran Nathan has a lot of questions he would like to answer. He has dedicated his professional life to birds and wants to reveal their secret lives.

"At this moment, we know nearly nothing about bird life. We just didn't have the technology before," he says.

But the new tracking device, which they call Atlas - Advanced Tracking and Localization of Animals in real-life Systems - has already delivered surprising results.

While tracking two pairs of barn owls, Nathan was once baffled to see how differently they behaved.

"One pair will forage only very locally, a few hundred meters away from its nest," he says. "The neighboring pair, though, will fly to the other side of the valley for each hunting event. It will fly back and forth to bring just one small rodent [to the nest]."

It is not only barn owls that Nathan is interested in. For instance, he wants to learn how often white storks cheat on their partners, or whether birds fly less when they molt.

Better than GPS

Up until now, the only way to monitor birds in real time was with GPS - the Global Positioning System. But GPS has some big disadvantages, Nathan says.

GPS transmitters drain batteries quickly, as they constantly communicate with satellites, and so only function for short periods.

"You can track barn owls with GPS for 3 days and 3 nights," says Yotam Orchan, an ecologist in Nathan's research group. "With our system, you can track them for four to six months."

There is a cost benefit, too.

"The new system is cheaper," Orchan says. One tag costs between 25 and 50 euros. "GPS tags for barn owls cost at least around 600 euros."

Atlas transmitters weigh just a few grams, so they can even be attached to small birds, such as passerines, bulbuls, kingfishers, or small bats.

The researchers glue the tags onto the birds' backs. And after a while, they simply fall off.

A paradise for birds

In Israel, the perfect location for bird research is the Hula Valley in the country's north.

Here, the researchers have set up their tracking station.

In the background, you can see the politically sensitive Golan Heights, a border between Israel and Lebanon and Syria.

But birds pay no mind to the human conflicts they fly around. Hula Valley is a popular stopover for migratory birds. They love the flat wetlands with its lakes, surrounded by big hills.

"Millions of birds migrate over here, during spring and fall," says Nathan.

Many species stay here for the winter, such as tens of thousands of cranes, which have become a big tourist attraction.

"Because of the unique position of Israel [at the border between several ecozones], we have a unique fauna here - and a unique interaction of species that do not meet each other in other places in the world," Nathan says.

It is not only a paradise for birds, but also for bird researchers.

International interest

Bird behavior researchers around the world are keen to test the new system in their own environments.

A consortium of international researchers plans to visit the Hula Valley this spring to learn how the system works.

One of them is Florian Jeltsch of Potsdam University, who studies wildlife in rural areas around Berlin.

"We hope to monitor a broader spectrum of birds with the Atlas system," he tells DW.

And he would like to test it with other animals: hares, foxes, raccoons, and even mice.

Tracking such tiny animals as mice is only possible with a system like Atlas, he says.

But there is a notable downside to Atlas. It doesn't work globally like GPS.

Researchers will need to set up ground stations in their respective areas. And if an animal leaves the defined area, the researchers lose the signal.

So researchers will have to think hard about where they set up their stations. For now, Israel's Hula Valley seems perfect.