Behavioural responses of captive-born greater rheas Rhea americana Linnaeus (Rheiformes, Rheidae) submitted to antipredator training

Abstract

ABSTRACT. Human activities have been diminishing greater rhea Rhea americana (Linnaeus, 1758) populations throughout their natural distribution. The reintroductions of captive-born greater rheas have been tried but without success; since the individuals reintroduced were killed by predators. Captive-born animals that have been isolated from predators for many generations can lose their predator recognition abilities. To enhance the survival rates of the reintroduced animals, researchers are now using antipredator training techniques. We studied the response of 15 zoo-borne greater rheas to antipredator training. The animals were divided into three groups: two test groups and one control group. We ran 15 antipredator tests and four control testes with each group. Antipredator tests consisted of pairing a taxidermized predator model or a real predator (domestic dog) with a simulation of a capture procedure. Control tests consisted of presenting the predator model (jaguar) to the birds, after training but not associating it with an aversive event and recording behavioural responses. All tests were video-recorded and analysed a posteriori. Results showed that the trained rheas responded appropriately to the predators, becoming more vigilant and that there was considerable individual differences in response to antipredator training. The results demonstrated that antipredator training is effective and therefore an invaluable tool for reintroduction projects involving greater rheas. Furthermore, the methods employed in this research project should be applicable to other species of flightless birds.

The rhea, a ratite native to South America

“…High vegetation habitat increases vigilance in both genders (Martella et al, 1995). Antipredator training of captive bred Greater rheas increases vigilance, although there are considerable individual differences between birds (de Azevedo and Young, 2006a). Considerable memory capacity is illustrated in that birds retained predator recognition for almost three months (de Azevedo and Young, 2006b), illustrating that antipredator training is worthwhile in future reintroduction programs for conservation of Greater rheas (de Azevedo and Young, 2006c).…”

Do captive-born greater rheas Rhea americana Linnaeus (Rheiformes, Rheidae) remember antipredator training?

“…Each animal received 15 training sessions, separated equally among the models, from June to September 2003 (AZEVEDO & YOUNG 2006).…”

The Value of Enrichment to Reintroduction Success

“…Understanding these considerations can increase success rates and provide baseline data against which to compare the results of reintroduction programs [Miller et al, ; Stoinski et al, ]. Important behavioral traits that may influence reintroduction success include locomotion skills (e.g., moving in complex environments, constructing home sites like dens and nests, and movement patterns), predator avoidance (recognition and evasion), foraging (including finding, identifying, acquiring, and handling food), interacting in social groups (including courtship, mating, and raising and training young), habitat selection, and avoiding conflicts with humans [Derrickson and Snyder, ; Beldon and McCown, ; Miller et al, ; Snyder et al, ; Griffin et al, ; McPhee, ; Stoinski et al, ; de Azevedo and Young, ; Alberts, ; Utt et al, ]. Reintroducing captive‐born animals with poor behavioral skills often results in high mortality rates [Griffin et al, ; Stoinski et al, ; McPhee and Silverman, ; Shier and Owings, ].…”

“…Closely linked to locomotion, reintroduced animals obviously must avoid predation to survive long enough to reproduce for programs to succeed. For many species, predation represents the most immediate threat to the survival of released animals, and indeed a substantial body of literature focuses on the importance of predator avoidance to reintroduction success [Miller et al, ; Griffin et al, ; McLean et al, ; Banks et al, ; McPhee, ; Rabin, ; McPhee and Silverman, ; de Azevedo and Young, ; Kraaijeveld‐Smit et al, ; Shier and Owings, ; Alberts, ]. Predation especially threatens captive‐reared animals or animals released into areas with novel predators, as reintroduced animals may not recognize predators or react appropriately [Miller et al, ; Maloney and McLean, ; McLean et al, ; Griffin et al, ; McPhee, ; de Azevedo and Young, ; Shier and Owings, ].…”

“…The threat of predation has prompted many reintroduction practitioners to use enrichment to improve predator avoidance skills in individuals prior to release [Miller et al, ; Maloney and McLean, ; Biggins et al, ; Griffin et al, ; de Azevedo and Young, ; Shier and Owings, ]. This usually entails presenting models of predators and delivering an aversive experience to individuals prior to release.…”