Meet Tom Stehn

April 27, 2006

Dear Journey North,

We’re down to only 7 whooping cranes left at Aransas. The other 207 whooping cranes have all migrated. Numerous sightings have been reported recently from Canada, and the first whooping cranes could be arriving at their nesting territories at Wood Buffalo National Park any day now. I would expect most and/or all of the remaining 7 cranes at Aransas would start the migration in the next week. However, occasionally there are a few whooping cranes remaining at Aransas in early May.

Everybirdy's Diferent, and That's a Good Thing
Why are whooping cranes so individualistic that some of the whooping cranes have nearly completed their 2,500 mile migration and others haven’t even started? Survival of wildlife species is aided by having some individuals a little bit different. Then, if something threatens the population, there likely will be a few different individuals not impacted by the danger. This trait of being slightly different from all the other members of a group is quite important biologically. It is something that you should be able to relate to! For example, do you prefer to wear the same clothes as your classmates? Do you all cut your hair the same way? Do you all watch the same television shows or play the same sports? Obviously you don’t. These are individual traits that you have, just as whooping cranes all act as individuals. Some whooping cranes migrate earlier; others leave a bit later. Some are much more tolerant of the presence of people; others fly off as soon as they see a person. Just as whooping cranes are similar to each other but show individual traits, you are the exact same way. You strive to be different, yet you choose friends that usually have interests in common with you.

The Trouble With Snow
More snow storms hit the Dakotas this past week. Last week I asked you to think about what dangers snow storms pose for the cranes. Whooping cranes are able to handle cold weather extremely well because they are warm-blooded animals. However, I can think of two big problems caused by snow.

1. Power Line Collisions. Snow storms encountered in the spring would halt the migration becaue of unfavorable winds. North and west winds would be associated with the storms, and the whooping cranes could not fly against these winds. Whooping cranes flying in strong winds and poor visibility in a snow storm would be in much more danger from being unable to avoid striking a power line. They might either be blown by the winds into the electrical line, or might not see the line because of the snow.
2. No Food for Fuel. Whooping cranes normally avoid the dangers of snow storms by staying on the ground and tucking their head under their wing and sleeping. But when the storm is over, the ground and sources of food may be covered up by snow, making it much harder to find food. Marshes may have frozen during the storm. Snow covering up food or ice covering ponds that make it very hard for whooping cranes to find food are the major problem for whooping cranes encountering spring blizzards. Fortunately, spring blizzards usually last only a few days and the whooping cranes can continue their migration.

A Question for You
Now here is a very difficult question. Why hasn’t a migration pattern evolved so that the younger non-breeding cranes would remain at Aransas for 2-3 years until they get mates and are ready to breed? By staying at Aransas for several years, they would avoid the dangers associated with making at least 5 migrations trips. Send your answer to:

Tom Stehn
Whooping Crane Coordinator
USFWS

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