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Life

Whooping crane recovery puts human chick 'parents' out of a job

By Brian Owens

26 July 2016

Two cranes in wetland with chick in the middle

International Crane Foundation

When this year’s clutch of captive-bred whooping cranes hatch at the International Crane Foundation (ICF) in Baraboo, Wisconsin, they’ll see something that previous generations missed out on – their parents.

The recovery of whooping cranes is one of conservation’s big success stories. From a low of just 21 individuals in the 1940s, the population has grown to more than 600 birds today. Around 100 of those make up the reintroduced “eastern migratory population” that breeds in Wisconsin and winters in Florida.

To boost their numbers, the ICF used a technique called “re-clutching”: the eggs are taken away from breeding pairs and hatched in an incubator, allowing the birds to lay more than one clutch in a season. This meant each pair could produce four or five eggs per year, instead of one or two.

But that also meant that there were more chicks than the adult birds could handle, so humans wearing crane costumes reared the young. Operation Migration volunteers in ultralight aircraft later guided the birds along the migration route to Florida.

The result was that lots of young birds were released into the wild, but they turned out to be not very successful in raising their own young. Last year just two chicks fledged in the wild.

So the US Fish and Wildlife Service recommended that the ICF end costume rearing and ultralight flights and let the birds raise their own chicks. “It lets them learn from other cranes how to defend their territory and hunt for food,” says Kim Boardman, curator of birds at the ICF. “It’s more natural.”

Single crane with brownish chick

International Crane Foundation

Kim Smith, also at the ICF, stresses that this doesn’t mean that costume rearing and guided migration was a failure. Indeed, getting the birds to raise their own chicks has always been the goal, she says. “We couldn’t have done it any other way at the beginning.”

Though the costumes and ultralights have become a popular feature of the organisation’s public outreach, Boardman says everyone is on board with the new system.

“Having worn the costume for many years, I can tell you it’s all about raising the best possible bird,” she says. “Whatever we have to do to make the population thrive, that’s what we’ll do.”

Read more: Meet the animals that are defying odds by escaping extinction

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