Abstract
Captive rearing of endangered species for later release is a method used to augment critically small populations, although studies have shown lower survival and fitness for individuals raised in captivity. Since 1992, recovery efforts for the endangered Great Lakes piping plover population have included captive rearing, but released young have lower survival than wild plover chicks. We tested the hypothesis that captive-reared chicks lack the ability to recognize predators by using visual and auditory stimuli. Vocalizations of predators and non-predators were combined with parental alarm calls, predator silhouettes, and a control to test for vigilant responses in captive-reared chicks prior to release. We tested for increases in average percent time spent on vigilant behaviors associated with exposure to predator and non-predator stimuli using linear mixed models. Chicks exhibited the greatest increase in vigilance when a treatment was combined with a parental alarm, regardless of whether the treatment was a predator or non-predator. Compared to white noise, average vigilance increased from 1.7% to 21.9% during non-predator treatments (95% CI: 8.0-34.2%) and to 78.3% during predator treatments (95% CI: 65.7-91.1%), indicating that chicks innately recognize avian predators as threatening. Average vigilance increased by 56.4% during predator treatments compared to non-predator treatments (95% CI: 49.8-64.8%), but individuals did not appear to differentiate between specific predators or non-predators. Our results provide strong evidence that captive-reared chicks innately recognize avian predators, which suggests that decreased post-release survival in captive-reared piping plovers is most likely caused by some other captivity-induced difference or by the lack of a parentally-taught behavior.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 153-162 |
| Number of pages | 10 |
| Journal | Applied Animal Behaviour Science |
| Volume | 144 |
| Issue number | 3-4 |
| DOIs | |
| State | Published - Mar 2013 |
Bibliographical note
Funding Information:We thank the University of Michigan Biological Station for continued support of piping plover captive rearing recovery efforts and for fellowship support of S.P.S. for this research. We are grateful to E. Roche and T. Arnold for analysis support. We also acknowledge B. Van Dam and T. Schneider for protocol advice and inspiration. The Detroit Zoological Society and many other zoological institutions participate in captive rearing of Great Lakes piping plovers, and we acknowledge their many important contributions. We thank B. Walker and J. Van Zoeren for assistance with data collection as well as M. Breyer, P. Rink, C. Ruggie Saunders, and C. Smith for their assistance in apparatus preparation and operation. Finally, we appreciate the insightful comments provided by two reviewers of the manuscript. Funding for this study was provided by the U.S. Fish and Wildlife Service and the Michigan Department of Natural Resources . F.J.C. was supported by funds from the Minnesota Agricultural Experiment Station .
Keywords
- Captive rearing
- Charadrius melodus
- Innate
- Piping plover
- Threat recognition
- Vigilance
