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2001 Fall Whooping Crane Migration
Still in Adams County, WI - Oct. 20, 2001
Vets Monitor Cranes During Migration
Weather: Continued Headwind
Flight length/duration: 12 miles & 22 min.
Heavy frost delayed the morning flight until 7:41am. Once airborn they found that there was a steady headwind. To be able to fly faster the pilot dropped to a lower altitude. Unfortunately, as they neared I-90/94 the birds appeared wary of the highway and the large noisy trucks that were using it and refused to cross the busy interstate at this low level. They turned around and returned to the take off location. The pilots hope that tomorrow the winds will shift and they'll be able to cross the Interstate at a higher altitude.
Stress - we hear a lot about it; the need to reduce it and how it affects our health. Just as stress affects humans, it can be as much of a concern for biologists and pilots leading a flock of whooping cranes south on migration.
How do you measure stress in a bird that stands five-and-a-half feet tall, has a very independent nature, and is rather fragile despite its height? Gently but frequently.
This has been a challenge for crane biologists for many years. Whooping cranes, like those in the current migration study, react to stress just as you or I would, but just like you or I, they may not exhibit outwardly any specific signs of being stressed.
During a recent study it was discovered that when whooping cranes are stressed they produce a specific hormone called cortagastarone. This hormone is initially released throughout the bird's body, but eventually is excreted in the bird's feces. This discovery gave biologists their first opportunity to monitor birds' stress levels without being invasive.
"We collect (feces) samples over a period of time," said Barry Hartup, veterinarian with the International Crane Foundation, "and then record the results of analysis for reference. Using this method allows us to get a sense of when the birds may be exhibiting a reaction to stress."
According to Hartup, this information then allows scientists and researchers to judge with some certainty when a bird is likely to become stressed, and of particular concern, over- stressed, which can lead to death.
During the migration study, veterinarians perform visual, non-invasive checks on the birds looking for outward signs of stress, injury or sickness. They also collect feces samples to analyze and track how the birds are handling their new experience.
Using this information along with the data collected during their last health check, veterinarians and crane biologists keep the birds healthy and ready to attempt the next leg of our trip south.
Last updated:
May 7, 2009