North American Crane Working Group
Proceedings of the North American Crane Workshop
Date of this Version
2023
Document Type
Article
Citation
Proceedings of the North American Crane Workshop (2023) 16: 146–156
Abstract
The reintroduced Eastern Migratory Population of whooping cranes (Grus americana) experiences low recruitment and high mortality. To support and supplement this population’s growth, ex-situ breeding and release programs prioritizing the release of juvenile whooping cranes (121.1 ± 2 days after hatch) are used. However, extenuating circumstances have resulted in the release of 4 after-hatch-year and 1 adult whooping crane between 2018 and 2022. Although the sample size is small, these unique cases are informative for future management and release, revealing lower survival 1 year after release (20%) than traditional release methods (parent-reared: 69.0%; costume-reared: 64.4%), and average post-release survival of 314.5 days and 39.0 days for spring and fall releases, respectively. Causes of mortality for the 5 released cranes in this study include emaciation, lead exposure, powerline collision, predation, and entrapment in a forest canopy. Additionally, monitoring of after-hatch-year and adult whooping cranes immediately post-release revealed a greater selection for forested and upland habitats than expected. Using the results of this study, we recommend limiting future releases of older birds, allowing only for spring releases under unique circumstances, and providing standing water, live food items, and predator aversion training for whooping cranes in captivity to encourage and support natural behaviors and higher survival.
Comments
Copyright 2025, North American Crane Working Group. Used by permission