Tom Stehn's Report: From Texas to Canada!
April 15, 2011
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As you read Tom's report this week . . .

  1. How many cranes remain at Aransas this week?
  2. When does Tom expect the remining cranes to depart, and what reason explains that?
  3. Why do the cranes go to Canada for nesting?
  4. What surprised you?


Meet USFWS Whooping Crane Coordinator Tom Stehn

Images: Klaus Nigge

Dear Journey North,

Wow! The census flight on April 13th only found 10 whooping cranes at Aransas, fewer than I expected. The migration seems to be about a week on the early side this year, with some cranes starting to cross the border into Canada. The 11 radio-banded cranes with satellite transmitters that let us know their exact whereabouts are currently spread out between Nebraska and North Dakota.

Who's Left at Aransas?
The 10 cranes still at Aransas included two family groups. I expect them to depart in the next week since they have to leave soon in order to get up to Wood Buffalo National Park in time to nest. So by next week, Aransas will be down to—at most—3 whooping cranes. Those 3 could stay into early May, and occasionally a crane or two fails to migrate and could spend the summer at Aransas. I assume the 3 are young birds not yet old enough to breed, so they have no sense of urgency to get to Canada to defend a territory and build a nest.

Why Migrate 2,500 Miles to Nest?
The blue crabs at Aransas are happy, no longer having to face the menacing 5-foot-tall great white cranes that stalk them throughout the winter. The marshes seem empty to me with the whooping cranes gone. Yet the species has evolved so that their best chance of producing young and increasing the size of the flock lies in making that 2,500-mile migration and nesting in the highly productive marshes of Canada where there are many fewer predators than there would be if the cranes remained at Aransas to nest.

Tom Stehn, Whooping Crane Coordinator
Aransas National Wildlife Refuge
Austwell, Texas