In 1975, experimental releases were made by placing nestlings, hatched in captivity, into the nests of wild parents - a method known as fostering. Cross-fostering involves placing peregrine chicks into the nests of the very similar, but more common, prairie falcon. Prairie falcons then raise foster peregrine chicks as their own. Hacking involves raising young birds by people. Biologists place young chicks in an artificial nest box located at a site that might normally be chosen for nesting.
Helpers provide constant care to the chicks while keeping out of sight of the growing birds.
The birds are released when they are ready to fly, not realizing that they were dependent on people. Re-establishing a breeding population is a slow process filled with risks. Birds are lost because of shooting, predation, bad weather and inexperience. Peregrines often do not breed before their third or fourth year, so two out of three young may die before reaching sexual maturity. No captive-bred birds were released in Newfoundland and Labrador.