Whooping Cranes Grus americana increased from 16 wild migratory birds in 1941 to about 146 birds in 1991. Management on the breeding range in Wood Buffalo National Park, Northwest Territories-Alberta, and protection of the birds along their migration route and on the winter range in Texas, are partly responsible for the population increase. The present Wood Buffalo National Park-Aransas National Wildlife Refuge flock consists of almost 50% non-breeders, mostly subadults. Further increases in the number of breeding pairs beyond the 1991 record of 33 can therefore be expected. The wild population has been a source of surplus eggs, whose removal has not adversely affected population growth. These eggs have been used to establish captive flocks, and captive-reared stock will be used to establish other populations. Attempts to establish a new migratory flock in Idaho by means of cross-fostering Whooping Crane eggs to Sandhill Cranes Grus canadensis have not been completely successful. Present plans call for the establishment of a non-migratory flock in Florida.