This Scientist Gives Flying Lessons to Birds

In the early 2000s, Fritz decided to help bring ibises back to Europe. But there was one big catch: The birds perform a seasonal migration. Youngsters bred in captivity knew they were supposed to fly away in late summer. But since none of the birds had lived in the wild, they didn’t know where to go. So Fritz decided to show them.

Using small aircraft, Fritz’s team started leading young ibises south. They flew from summer breeding grounds in Germany and Austria to a winter refuge in Italy, crossing over the Alps mountains (see Flight Map). After just one flight, many of the birds continue migrating and pass the route on to their young.

Over the past 20 years, Fritz’s team has trained and released hundreds of ibises. But climate change is throwing a wrench into this success story. As average global temperatures rise, warm summer weather in Europe persists longer than it did in the past. Without an early fall chill to trigger the ibises’ departure, previously released birds are starting their migration later in the year, with disastrous consequences. Now Fritz is on a mission to save the ibises again—by teaching them a new migration route for a changing climate.

In the early 2000s, Fritz decided to help bring wild ibises back to Europe. But he faced a big problem. The birds perform a seasonal migration. Young birds knew to fly away in late summer. But they had been bred in captivity. None of them had lived in the wild, and they didn’t know where to go. So Fritz decided to show them.

Fritz’s team used small aircraft to lead young ibises south. They took off from summer breeding grounds in Germany and Austria. Their journey ended at a winter refuge in Italy. On the way, they crossed over the Alps mountains (see Flight Map). After just one flight, many of the birds continue migrating. They pass the route on to their young.

Over the past 20 years, Fritz’s team has trained and released hundreds of ibises. But climate change is interfering with this success story. Average global temperatures are rising, and warm summer weather in Europe lasts longer than before. There isn’t an early fall chill to tell the ibises to leave. The birds that were already released are starting their migration later in the year. And the results are tragic. Now Fritz is working to save the ibises again. He’s teaching them a new migration route for a changing climate.

Fritz first encountered ibises in the 1990s while working on his Ph.D. at an Austrian research station. Scientists there had started raising ibis chicks received from a zoo. “Then one morning in August, all of the chicks were gone,” Fritz recalls. “We searched the surrounding valley. We had no idea where they went.” Over the next few months, scientists and birdwatchers reported ibises in the Netherlands, Poland, Russia, and Hungary. Many of the birds were found dead. The rest went missing soon after they were spotted.

Unsure if the flock’s disappearance from Austria was a fluke, the scientists raised chicks again the next year. The same thing happened. “It became clear that these birds were performing migration behavior, even after generations in zoos,” says Fritz. The birds still had the instinct, or natural tendency, to migrate. But without experienced parents to show them the way, the young ibises had no idea where to fly.

Fritz first met ibises in the 1990s. He was working on his Ph.D. at an Austrian research station. Scientists there were raising ibis chicks received from a zoo. “Then one morning in August, all of the chicks were gone,” Fritz recalls. “We searched the surrounding valley. We had no idea where they went.” Over the next few months, scientists and birdwatchers spotted the ibises. The birds appeared in the Netherlands, Poland, Russia, and Hungary. Many ibises were found dead. The rest soon went missing.

Was the flock’s disappearance from Austria just a fluke? The scientists weren’t sure. So they raised chicks again the next year. The same thing happened. “It became clear that these birds were performing migration behavior, even after generations in zoos,” says Fritz. The birds still had the instinct, or natural tendency, to migrate. But they didn’t have experienced parents to show them the way. So the young ibises didn’t know where to fly.

Fritz had heard about Canadian artist and naturalist Bill Lishman, who in the 1980s pioneered the technique of leading migrating birds with small aircraft. Lishman—whose story was fictionalized in the 1996 movie Fly Away Home—had flown with Canada geese and endangered whooping cranes. “I was inspired and thought this might work with bald ibises,” says Fritz.

Fritz and his colleagues developed a process for helping ibises bond with human foster parents, who ride in the aircraft. This technique relies on imprinting—the formation of a strong attachment between a young animal and a parent figure (see Raising Ibises). “During migration, the birds don’t follow the aircraft,” he explains. “They follow the foster parent. That relationship is crucial.”

In 2004, Fritz led a successful ibis migration flight to a winter refuge in Italy. Eventually, adult birds began migrating back to Austria on their own. “The return of the first bird was a key moment for us,” says Fritz. It showed that reintroduced ibises could remember their migration path and make the trip without help.

Leading the flights is hard work. The journey takes weeks, with stops overnight to rest. In the air, pilots and foster parents must constantly monitor the flock. To save energy, the birds change altitude, switch between flapping and soaring, and adjust their flight formation to weather conditions. “The birds are not just following,” says Fritz. “We must always watch and maneuver with them.”

Fritz had heard about Bill Lishman, a Canadian artist and naturalist. In the 1980s, Lishman led migrating birds with small aircraft. The story was fictionalized in the 1996 movie Fly Away Home. Lishman flew with Canada geese and endangered whooping cranes. “I was inspired and thought this might work with bald ibises,” says Fritz.

Fritz and his colleagues found a way to help ibises bond with human foster parents. Then the foster parents ride in the aircraft. This process relies on imprinting. That’s when a young animal forms a strong attachment with a parent figure (see Raising Ibises). “During migration, the birds don’t follow the aircraft,” he explains. “They follow the foster parent. That relationship is crucial.”

In 2004, Fritz led ibises to a winter refuge in Italy. The migration flight was a success. Over time, adult birds began migrating back to Austria on their own. “The return of the first bird was a key moment for us,” says Fritz. It showed that reintroduced ibises could remember their migration path. So they could make the trip without help.

Leading the flights is hard work. The journey takes weeks, with overnight rest stops. In the air, pilots and foster parents must constantly watch the flock. To save energy, the birds change altitude. They also switch between flapping and soaring. And they adjust their flight formation to weather conditions. “The birds are not just following,” says Fritz. “We must always watch and maneuver with them.”

Captive-raised birds, which are trained and released regularly, have continued to migrate and reproduce in the wild. As a result, Europe’s ibis population has been growing. “But now we face a serious new problem: climate change,” says Fritz.

As warm spells in early autumn last longer, flocks migrating on their own depart later. Too late, in fact. In recent years, the birds made it to the Alps but were unable to cross the mountains before wintry weather set in. “We had to capture the birds, transfer them in crates, and release them on the other side,” says Fritz. Otherwise, the ibises would have starved or frozen to death.

But driving the birds wasn’t a long-term solution. “We needed an alternative, or the reintroduced population would become extinct within a few years,” says Fritz. So last year, he devised a new route to a wintering area in Spain. The 2,300 kilometer (1,400 mile)-long trip is three times the length of previous paths. But it skirts around the Alps instead of crossing them. So even if the ibises get a late start, they won’t be thwarted by cold and should be able to complete their journey.

When Fritz spoke with Science World, he’d been flying with the birds for five weeks. About 10 days later, they reached the ibises’ winter destination in Spain. Fritz will be watching anxiously for the ibises’ return in the spring. He remains hopeful that the birds he loves can beat the odds again. “With some support, we have a chance for the northern bald ibis to survive and sustain itself in a changing world,” says Fritz.

Captive-raised birds are trained and released regularly. They have continued to migrate and reproduce in the wild. So Europe’s ibis population has been growing. “But now we face a serious new problem: climate change,” says Fritz.

Warm spells in early autumn last longer. So flocks that migrate on their own leave later. Too late, in fact. In recent years, the birds made it to the Alps. But they couldn’t cross the mountains before winter weather began. “We had to capture the birds, transfer them in crates, and release them on the other side,” says Fritz. Otherwise, the ibises would have starved or frozen to death.

But transferring birds in vehicles wasn’t a long-term solution. “We needed an alternative, or the reintroduced population would become extinct within a few years,” says Fritz. So last year, he planned a new route. The 2,300 kilometer (1,400 mile)-long trip ends at a wintering area in Spain. It’s three times as long as previous paths. But it doesn’t cross the Alps. Instead, it goes around them. So the ibises won’t be stopped by cold, even if they get a late start. They should be able to complete their journey.

Fritz spoke with Science World five weeks into his flight with the birds. About 10 days later, they reached the ibises’ winter destination in Spain. Fritz will watch anxiously for the ibises’ return in the spring. He loves the birds, and he hopes they can beat the odds again. “With some support, we have a chance for the northern bald ibis to survive and sustain itself in a changing world,” says Fritz.