Parenting a flock of Northern Bald Ibises is a demanding job. For the past six months, biologists Barbara Steininger and Helena Wehner have spent every day hand-feeding and raising dozens of these endangered chicks. They couldn’t pass their fostering duties off on anyone else during that time—the juvenile birds needed to imprint on them and them alone.
Steininger and Wehner then took to the skies to guide their young charges on the birds’ first migration. In mid-August they climbed onboard a microlight aircraft in Rosegg, Austria, to start their approximately 2,800-kilometer journey, which ended on October 3 at a wintering site in Andalusia, Spain. There the two foster parents said their final goodbye to the birds that they helped raise.
“At the end, you have to release them in the wintering site and accept that they are now independent and don’t need you anymore,” says Johannes Fritz, who leads the team reintroducing Northern Bald Ibises to the wild in Europe and has been piloting the microlight aircraft on these guided migrations since 2004.
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Northern Bald Ibises migrating.
Waldrappteam Conservation and Research
Bald Ibis Migration
Each fall, when the days grow shorter and the weather cooler, the ibises’ migratory instinct kicks in, priming them to seek out a warmer climate to spend the winter. Normally parents would guide their young on their first migration to show them the route. But the birds’ knowledge of their flight path has been largely lost. That’s because the species has been hunted nearly to extinction in its native habitat of North Africa, Central Europe and the Middle East. In Europe the species was in trouble as early as 1504, when the Archbishop of Salzburg decreed it illegal to shoot the birds. Despite this ban and other early conservation efforts, the Northern Bald Ibis was last seen in the wild in Europe in 1621, and only a small number have survived, mainly in Morocco.
Today, thanks to careful management and reintroduction efforts, some small sedentary (nonmigrating) populations live in the wild in Türkiye and Spain. But their inability to migrate might actually threaten their survival. Migratory birds evolved to reproduce in one climate and spend the winter in another. Splitting their time between two habitats can give them better access to food and higher reproductive success, explains Ana González-Prieto, an avian ecologist at the Canadian Wildlife Service, who is not involved in the reintroduction effort.
To have the best shot at success in the wild, Northern Bald Ibis populations need to migrate, Fritz says. So his team has taken on the responsibility of teaching young birds the route themselves. They were initially inspired by the 1996 movie Fly Away Home, in which a girl and her father help a flock of geese migrate using an ultralight aircraft. The movie was based on the work of the late Bill Lishman, a sculptor and filmmaker who used such an aircraft to teach captive-raised birds to migrate. Lishman co-founded Operation Migration, an organization that deployed bird-costumed scientists to guide endangered birds such as Whooping Cranes, once nearly extinct, on migratory routes across North America.
Fly Away Home with Bald Ibises
This method, called human-led migration, is both resource- and time-intensive, but for the Bald Ibises, it appears to be working. The process starts in the spring with foster parents who hand-rear chicks taken from captive-bred populations. Then, come late summer, the conservation team sets out on its route. A microlight aircraft powered by a propellor and kept aloft by a large yellow parachute takes off, soaring hundreds of meters above the ground. It flies at the speed of the birds, no faster than 50 kilometers per hour. The flying contraption seats two people—Fritz, who got his pilot’s license for this very purpose, and one of the two foster parents, who trade off on sky duty.
As the aircraft takes off, the foster parent calls out in German for the birds to follow, shouting “Komm, komm!” through a megaphone over the drone of the engine. Once in the air, the birds will sometimes fly close to the aircraft and greet the foster parent by moving their bill up and down and calling out. After the foster parent greets them back, they take their position in the formation.
“It’s very emotional,” Fritz says. “I have the privilege as pilot to experience this in the sky.”
After four or five hours of flying, they land back on the ground. At least a dozen other crew members will have driven ahead to set up camp: a temporary aviary for the birds and tents for the team members. The next day, they do it all over again.
This year Fritz’s team shepherded 36 birds, its largest-ever group of juvenile Northern Bald Ibises. But just like human adolescents, the birds do not always cooperate. This trip was “a little bit stressful because the birds refuse to follow” at times, Fritz says. Sometimes when the aircraft took off, the birds stayed on the ground. “The foster mother is calling the birds [as] we circle in the distance,” Fritz says, “but they remain on the airfield.”
These changes in the birds’ “motivational state” are challenging but normal, Fritz says. If the aircraft circled back enough times, the birds did eventually follow—being apart from their foster parent temporarily is “a kind of social punishment,” he says. “When they follow, then they are rewarded just by contact with the foster parent.”
Early this month, all 36 birds arrived in Andalusia—though only 10 managed to fly the entire way themselves. The remaining 26 were transported for the final leg of the trip. They are joining an existing group of reintroduced Northern Bald Ibises and will spend their first balmy winter in the wild. Once the days begin to lengthen again, they will hopefully migrate on their own back to the Alps to breed. Most of the birds are tagged with solar-powered GPS tags so conservationists can monitor and manage the wild population.
Reaching a Sustainable Population
In the early years of the program, no birds returned to the Alps from their initial wintering site in Tuscany, Italy. Then, in July 2011, the first bird made it back. In the four generations since then, the wild migratory population has grown to 256 birds. They have a relatively high reproductive success rate, with around three chicks fledged per nest, compared with sedentary populations in Andalusia, which produce only about one chick per nest on average.
Until the population reaches a sustainable level, the researchers will need to continue hand-rearing and guiding more chicks on their first migration. A study published in 2023 found that the population is close to being self-sustainable—or able to thrive without human intervention—but has not yet crossed that threshold. The program currently has partial funding through the European Union secured through 2028.
Northern Bald Ibises migrating in formation.
Waldrappteam Conservation and Research
The original human-led migration organization, Operation Migration, flew with Whooping Cranes from Wisconsin to Florida from 2001 through 2015. It restored a migrating population of the birds, but they didn’t reproduce successfully enough to reach a self-sustaining population. The U.S. Fish and Wildlife Service ultimately pulled its support from the project.
Both the Whooping Crane and Bald Ibis programs are experimental and invasive. And they are highly visible to the public. “There was a lot of skepticism in the early years of the project,” Fritz says. “Meanwhile I think the scientific community and the conservationists recognize the potential of the methods.”
“The primary strength of these projects is their positive conservation outcomes, as evidenced by the increase of wild populations,” González-Prieto says. “They also inspire action to protect other declining wild breeding populations before they also face extinction” because they demonstrate how resource-intensive it can be to bring a species back from local extinction.
Methods like these might become increasingly important as climate change continues to alter how birds migrate and where they spend their winters. Fritz’s team originally flew its birds over the Alps to Tuscany, but the reintroduced birds have been leaving their summer homes later and later each year because of climate change—rather than late summer, they’re waiting until autumn.
“These birds have delayed their migration until early November, when thermal [air currents] are too weak to support their journey over the Alps,” González-Prieto says. “As a result, birds become stuck in unsuitable valley habitats.”
Last year Fritz’s team began flying the birds to Spain instead of Italy, a path that doesn’t require them to cross the Alps. As these changes to the environment continue, humans might need to intervene more and more to ensure species continue to migrate. “These changes in times of climate change are simply much too fast for the species to cope with,” he says.
“It’s clear that the extinction of the Bald Ibis is the responsibility of the humans,” he adds. “I think it’s worth doing whatever possible” to save them.
