Whooping Crane Migration Update: March 11, 1997

Claudia Fonkert, Macalester College

TO: Journey North
FROM: Tom Stehn, Aransas NWR
Date: March 11, 1997

Dear Students,

The whooping crane migration is underway! I got a telephone call from Wally Jobman of USFWS in Nebraska that a single whooping crane was sighted on the Platte River on March 9. This is way ahead of the normal whooping crane migration. Although I can remember one instance where cranes left Aransas the first week in March, most cranes leave the first two weeks in April. If the cranes leave too early, they run into more severe weather and may encounter all the ponds iced over on their nesting grounds. The cranes that leave Aransas early tend to make a slower migration trip, whereas cranes that leave here in the middle of April will take only 2-3 weeks to fly the 2,500 miles to Wood Buffalo. How do the cranes "know" to do this?

Why is a single whooper already on the Platte River?
The answer is probably tied in with sandhill crane biology. Sandhills leave Texas much earlier than the whoopers, then "stage" on the Platte River in Nebraska, spending a long time there building up fat reserves and finding mates. I think the single whooping crane joined its sandhill cousins and got swept up in the excitement to Nebraska.

Is this single whooper one of the 158 birds I've been monitoring all winter? I don't know for sure, but it may not be. I counted all 158 cranes on an aerial flight March 5. Since it normally takes one week for cranes to fly between Aransas and the Platte River, I think it unlikely that the single whooper left Aransas after my March 5 count and was in Nebraska 4 days later. What makes more sense to me involve three unconfirmed sightings of a whooping crane this winter sighted in West Texas just south of Lubbock. We consider these sightings as "unconfirmed" because a trained biologist did not observe the bird. But three separate sightings is intriguing to me. I think this bird that wintered with sandhills, migrated with its cousins is the bird now in Nebraska. If this is true, than we have to add one more crane to the population, which would be 159 presently in the wild flock. This is one theory that I can't yet prove. Maybe I'll learn more on my next count at Aransas.

Unless there's breaking news from Tom...

The Next Whooping Crane Migration Update Will be Posted on March 20, 1997