Operation Migration Puts Crane Call Recordings to Work

Dr. Wessling gets ready to test the sound system that will play his recorded crane calls.
Bernard Wessling's crane voiceprint studies are a great new way for recognizing individual cranes. Making recordings of individual crane voices avoids stressing the birds by capturing and banding them. That means voiceprints are much safer for an endangered species like the Whooping Crane. The voiceprints have helped show how cranes use vocal calls to communicate among themselves. Dr.Wessling's recordings have also made it much easier to train cranes to follow planes—a real help for the Operation Migration crew. (Operation Migration is a Canadian organization that pioneered in using ultralight airplanes to teach migration routes to birds without adults of their species to show them the way.)

Why was such a project necessary? Migration is a behavior most birds learn from other members of their flocks. With no wild Whooping Cranes in the East, experts hoped Ooperation Migration's tiny airplanes and costumed pilots could do what Whooper parents do naturally. The Sandhill Cranes in the 2000 "trial run" were collected as eggs from the wild; they had no one but humans (with crane puppets) to teach them their migration route. If all went well with the Sandhill migration experiment, the next year (2001) Operation Migration's team would begin teaching Whooping Crane chicks hatched in captivity (and raised by humans) a migration route between their ancient nesting grounds and a wintering ground 1,200 miles away.
Speaker on the Ultralight
Wayne Kryduba
Dr. Wessling's recorded crane calls play a big role in the success of Operation Migration's work with cranes. The ultralight-led Sandhill Crane migration in 2000 "marks the first time we are talking to the cranes in crane language."

Vocal Calls Send Meanings
Dr. Wessling had collected six crane sounds for Operation Migration. The sounds are the calls that cranes use to communicate vocally. An adult uses the contact call or brood call, for example, to say to a chick: "It's okay. Follow me!" Each sound is a code, much like the code we understand when someone says "Shhhhh." The six vocal codes collected by Dr. Wessling mean these things to cranes:

  1. "Attention, please! Danger!"
  2. "Do not land here! Keep flying."
  3. "No problem."
  4. "Come here. There's some food."
  5. "Do not enter. This is my territory!" Listen to hear the guard call.
  6. "We are a pair. We belong together and this is our territory." Listen to hear the unison call.

Train-the-Crane Success
Photo Operation Migration
The vocal code recordings were used to train the Operation Migration Sandhill Cranes to follow the ultralight. Dr. Wessling visited the Operation Migration staff in August 2000 to work with them and the cranes. As you might expect, the cranes learned much faster when trained with "Crane-glish." The calls were played to the cranes from the time they were still in their eggs.

Those six calls would be played through hand-held players concealed on people who fed the cranes, and from the crane puppets to "talk" to the cranes. They
Photo Operation Migration
were played from a CD through big megaphones on the ultralight to talk to the cranes in the air.

Dr. Wessling's research was valuable. "Hearing the recorded sounds made the cranes better understand the training strategy and do what the trainers wanted them to do. We can ask the cranes to follow either the airplane, or caretaker #1 or #2, or whomever is calling them," said Dr. Wessling.

The Power of Acoustic Communication
Once some cranes were lured away during training by a pair of wild Sandhill Cranes. What now? The trainers played the recordings and the cranes came back! Another time, it was impossible to land the plane on the island where the pilots wanted to move the cranes to adapt them to the wild. How could they get the cranes to the island where the plane couldn't easily land? Members of the ground crew hid behind a blind on the island with a megaphone and a CD so they could play the calls. The plane flew into sight with the Sandhills behind, made several turns over the island, and stopped playing crane calls. That's when the people on the island immediately began playing calls with their megaphone and CD. The cranes got a little confused, but they heard the "mother" call from the island so they went down and landed. The experts were thrilled to see what the recorded calls could do. That's putting crane calls to work!

Try This! Journaling Questions

  • Why are crane calls a good way to keep track of individual Whooping Cranes? Give at least two reasons.
  • What would you like to ask Dr. Wessling if you could interview him?
  • Imagine you are Dr. Wessling. Listen to the calls he recorded from two different crane species. What's the difference?


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