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Providing evidence to improve practice

Individual study: Enhancement of whooping crane Grus americana recruitment by egg removal, Wood Buffalo National Park, Alberta and Northwest Territories, Canada

Published source details

Boyce M.S., Lele S.R. & Johns B.W. (2005) Whooping crane recruitment enhanced by egg removal. Biological Conservation, 126, 395-401


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Remove eggs from wild nests to increase reproductive output Bird Conservation

A replicated controlled study in Northwest Territories and Alberta, Canada, between 1967 and 1996 (Boyce et al. 2005) found that the reproductive success of wild whooping cranes Grus americana was higher for nests that had one of two eggs removed, compared to control nests. Both recruitment of juveniles to the population and survival until August (eggs were removed in May) were higher (50% chance of recruitment from nests with eggs removed vs. 39% for unmanipulated nests). A total of 496 eggs were removed from wild nests in the study period, representing 62% of all crane nests during this time period. The success of artificially incubating and rearing the removed eggs is discussed in Kuyt (1996) in ‘Captive breeding, rearing and releases (ex situ conservation)’.

Kuyt, E. (1996) Reproductive manipulation in the whooping crane Grus americana. Bird Conservation International, 6, 3–10.