TODAY | January 25, 2014
>>> a flock of 9-month-old whooping cranes will spend the next few months in florida after making the trip south from wisconsin .
>> they were guided there not by their parents but by ultralight aircraft . it's all part of an operation run by a dedicated group of volunteers who are determined to rescue the endangered species . it's not your typical bird call . but for eight young whooping cranes hatched in captivity, the sound of that engine clearly signals one thing, it's time to fly.
>> it starts out when they're still in the egg. we play a recording of the aircraft engines .
>> reporter: all part of an effort to create an environment that's as natural as possible for these birds, who must migrate south but don't have a parent to show them the way. joe duff is co-founder of "operation migration," a non-profit that uses ultralight aircraft to help these endangered birds learn to soar.
>> we start by just running up and down the runway with the birds. at some point, the penny drops and they realize they can fly.
>> reporter: once comfortable in the sky, the ultralights guide the cranes on a planned migration route from wisconsin to florida .
>> by showing them the route, same as their parents did, it works. they come back on their own.
>> reporter: duff and his volunteers don't want the birds to be comfortable around humans, so they wear these white suits to hide any trace of the person underneath, and they never speak around the birds, exposing them only to the sounds of nature, and of course, to the ultralight. when the endangered species act was signed 40 years ago, there were less than 50 whooping cranes in the wild. they now number almost 400. how many of those birds are a direct result of your efforts?
>> well, the whooping crane partnership has about 100 birds now migrating between wisconsin and florida .
>> reporter: the population is still fragile, threatened by both natural predators, including black flies , and by humans. two adult cranes trained by "operation migration" were shot in kentucky at the end of november. both birds died. a $15,000 reward was just announced for any information about the shooting. all of these threats are a major concern for duff, who stresses, the efforts to save these birds reach far beyond the cranes.
>> whooping cranes inhabit wetlands, and wetlands are a critical ecosystem for people. they absorb water when we have a flood, they hold water when we have a drought, they purify heavy metals and pollution.
>> reporter: three months and over 1,000 miles later, the journey followed closely online by people around the world, duff and his team arrived safely in florida . true success, however, comes when these birds make their way back to wisconsin where their journey began.
>> you get close to this. i mean, that's proof of our work.
>> reporter: work that has truly become a labor of love. joe duff also told me, this is really important to him, the day we were there was his daughter's 14th birthday, and he said i want my daughter to see these birds and i want them to be around for her, too.