Timing

• The first cranes could leave as early as the beginning of April. The migration is usually complete by mid to late May, 2 to 6 weeks later.

Tracking Method

• Departure from wintering grounds: The cranes depart in small family groups. Biologist Tom Stehn flies over the refuge 1-2 times a month. You'll find his crane counts in our Migration Updates.

• Along migration route: Reports come from confirmed visual sightings along the migration route. Ranger Martha Tacha of the U.S. Fish and Wildlife Service office in Nebraska facilitates the reporting network.

• Arrival on nesting grounds: As the cranes travel through Canada and complete their migration to the nesting grounds, Brian Johns, biologist with the Canadian Wildlife Service, sends the news.

Timing

• The older cranes leave first, and they could leave as early as the end of March. The migration is usually complete by mid to late April.

Tracking Method
For traditional classroom mapping, the eastern flock is the focus. The flock's youngest cranes are monitored the most closely.

• Departure from wintering grounds: People in Florida monitor the year's youngest cranes.

• Along migration route: The cranes are tracked by a combination of visual sightings and signals from radio and satellite telemetry. Trackers make every effort to track them from the moment they leave the wintering grounds until all have been accounted for on the nesting grounds. Their reports and technology give us a source of data points to map.

• Arrival on nesting grounds:People eagerly await the cranes' arrival in Wisconsin. We expect frequent news as the cranes complete migration. Students can maintain an Arrival Log (update coming Feb. 1, 2010) for all of the cranes in this flock.