Allen had begun an effort at captive breeding with a female crane named 'Josephine', the sole survivor of the Louisiana population, injured and taken into captivity in 1940, and two successive injured birds from the migratory population, 'Pete' and 'Crip', at the Audubon Zoo and the Aransas refuge. Josephine and Crip produced the first whooping crane born in captivity in 1950, but this chick only lived four days, and though decades of further efforts produced more than 50 eggs before Josephine's death in 1965, only four chicks survived to adulthood and none of them bred. At the same time, the wild population was not thriving. In spite of the efforts of conservationists, the aging wild population would gain only 10 birds in the first 25 years of monitoring, with entire years passing without a single new juvenile joining those that returned to the Texas wintering grounds. This led to a renewed tension between those who favored efforts to preserve the wild population and others seeing a captive breeding program as the only hope for whooping crane survival, even though it must depend on individuals withdrawn from the extremely-vulnerable wild population.