A brief description of each flock will aid you in interpreting the map:
The original wild flock is made up of birds that have always lived in natural circumstances. This flock of Whooping Cranes is the only naturally occurring wild population in the world. Two other flocks are formed by Whooping cranes hatched and reared in captivity and reintroduced into the wild. Until these two flocks establish themselves by reproducing and adapting to the natural environment, they are considered as experimental.
The wild Whooping Crane flock spends its summers in Wood Buffalo National Park in the Northwest Territories of Canada. They nest and rear their young there. During the fall season, the Whoopers migrate 2,500 miles south to Aransas National Wildlife Refuge in Texas where they spend the winter and early spring.
Beginning in 1993, a second flock of Whooping Cranes was reintroduced in central Florida. An average of 20 chicks, hatched and reared in captivity, were released at the Florida site each year in an effort to establish a new flock of non-migratory Whoopers. Some of these birds have matured and began nesting. In 2002, the first Whooping Crane in this flock fledged. This Florida non-migratory flock is no longer receiving release captive reared whooper chick. It has experienced high mortality and low reproduction. Biologists continue to monitor the remaining birds in the Florida non-migratory flock to study the problems.
Attempts to establish a third Whooping Crane flock was initiated in 2001. This will be a migratory flock. Birds used in this flock have also been hatched and reared in captivity and trained to migrate following an ultralight aircraft. They currently spend spring and summer at Necedah National Wildlife Refuge in Wisconsin and migrate to Chassahowitzka National Wildlife Refuge in west Florida for winter. Several groups of ultralight led Whoopers have completed their migratory journey. Some of the older whoopers have nested and hatched young. Survival of chicks has been disappointing as of 2010. But managers remain optimistic because this population is still relatively young and is in a learning mode.