Chick Hatching and Rearing
Whooping cranes being released in this reintroduction project come from captive whooping crane flocks in Maryland (program closed in 2017), Wisconsin, and Alberta. Eggs laid by captive birds are hatched in incubators and chicks are then raised by project personnel under strict protocols designed to prevent the chicks from imprinting on humans.
Training and Releasing Cranes
From 2001 until 2016, whooping crane chicks were transported to Wisconsin in June where they were conditioned to follow ultralight aircraft in preparation for their assisted fall migration to wintering grounds in Florida.
Cranes were imprinted on the small aircraft, which guided them along a safe migration route.Beginning in 2005 the ultralight-led migration was supplemented with a second reintroduction technique called Direct Autumn Release (DAR). Young cranes are released in small groups with wild whooping cranes, with the intent that they will learn the migration route from these older, more experienced birds. After learning the migration route by following the ultralight aircraft or older cranes to the wintering areas, the young cranes make the return flight to their summering grounds in the north on their own the following spring.
After 2015, cranes were no longer led by ultralights on their first migration. Instead, all captive-bred chicks will be released with adult Whooping cranes that already know a migration route.
After several years of successful experimentation, beginning in 2016, a method called the Parent-reared release method is the main rearing and release method used. This method involves having captive parent cranes hatch and raise the youngsters with minimal contact with humans. When the birds are ready for release, they are transferred to Wisconsin where they are released into the company of free-ranging adult cranes that do not have their own wild-hatched young. The hopes are that the young birds will learn more natural “crane like” behaviors from the captive adults, ultimately making the offspring more attentive and when it comes time for them to begin breeding.
All birds are banded with a unique combination of color bands to allow for their identification in the field. Every bird is also outfitted with a VHF transmitter that allows biologists to track their locations with handheld receivers. Some of the cranes also carry satellite and cellular-based transmitters which allow us to locate them if they are lost or out of range of traditional receivers and to track them year round. WCEP project biologists track and monitor the released cranes in an effort to learn as much as possible about migration behaviors, habitat selection, and to monitor movements and survival. Results of monitoring are reported in the Project Updates.