Cooperative Fish and Wildlife Research Units Program: Minnesota
Education, Research and Technical Assistance for Managing Our Natural Resources

Severud, W.J., D.Wolfson, J. Fieberg, and D.E. Andersen. 2022. Sandhill crane colt survival in Minnesota. Journal of Fish and Wildlife Management


Age-structured population models require reliable estimates of cohort-specific survival rates, yet vital rates of younger age classes are often difficult to estimate because of the logistical challenges of monitoring young animals. As part of a study of sandhill cranes Antigone canadensis in the zone of contact between breeding distributions of the Eastern Population and Mid-continent Population in Minnesota, United States, we monitored first summer survival of 34 sandhill cranes (hereafter, “colts”) using VHF and/or GPS-GSM transmitters. We estimated daily survival probabilities from 19 to 120 days post-hatch using a generalized linear model accounting for interval censoring, resulting in an estimated period survival rate of 0.52 (90% confidence interval 0.36–0.71) over summer (100 days). Estimated daily probabilities of survival increased as colts became older and fledged (at 70–75 days post-hatch), when they presumably became less vulnerable to predation. Causes of mortality were mostly unknown aside from one case of a collision with a vehicle. There is a scarcity of published colt survival rate estimates for sandhill cranes and what is available varies widely by study site. Region-specific sandhill crane colt survival rate estimates can inform future management efforts and inform population dynamics research and overall natural history knowledge of sandhill cranes.