Action: Use captive breeding to increase or maintain populations of cranes
A study from Canada over 32 years found that whooping cranes Grus americana successfully bred in captivity eight years after the first eggs were removed from the wild. The authors note that young ‘downy’ chicks suffered high mortality in captivity.
Supporting evidence from individual studies
A study between 1967 and 1991 (Kuyt 1996) found that the removal of 355 whooping crane, Grus Americana, eggs from a wild population in Northwest Territories and Alberta, Canada, to start a captive population, did not negatively affect the wild population, which increased from 48 to 146 birds during the study period, with no nests being abandoned. The captive population had high hatching success (78–100% for 50 eggs shipped to Patuxent Wildlife Research Centre in 1967-74, and 77% for 166 eggs shipped to Grays Lake National Wildlife Refuge in 1975-88) but ‘downy young’ suffered 68% mortality, mainly due to disease and anatomical abnormalities. However, cranes first bred in captivity in 1975 (in Patuxent), with five females laying 19 eggs in 1989 (nine hatching). This study is also discussed in ‘Release captive-bred individuals’, ‘Foster eggs or chicks with wild conspecifics’ and ‘Foster eggs or chicks with wild non-conspecifics (cross-fostering)’.