Training fails to elicit behavioral change in a marsupial suffering evolutionary loss of antipredator behaviors

Attempts to reintroduce threatened species from ex situ populations (zoos or predator-free sanctuaries) regularly fail because of predation. When removed from their natural predators, animals may lose their ability to recognize predators and thus fail to adopt appropriate antipredator behaviors. Recently, northern quolls (Dasyurus hallucatus; Dasyuromorpha: Dasyuridae) conserved on a predator-free “island ark” for 13 generations were found to have no recognition of dingoes, a natural predator with which they had coevolved on mainland Australia for about 8,000 years. A subsequent reintroduction attempt using quolls acquired from this island ark failed due to predation by dingoes. In this study, we tested whether instrumental conditioning could be used to improve predator recognition in captive quolls sourced from a predator-free “island ark.” We used a previously successful scent-recognition assay (a giving-up density experiment) to compare predator-scent recognition of captive-born island animals before and after antipredator training. Our training was delivered by pairing live predators (dingo and domestic dog) with an electrified cage floor in repeat trials such that, when the predators were present, foraging animals would receive a shock. Our training methodology did not result in any discernible change in the ability of quolls to recognize and avoid dingo scent after training. We conclude either that our particular training method was ineffective (though ethically permissible); or that because these quolls appear unable to recognize natural predators, predator recognition may be extremely difficult to impart in a captive setting given ethical constraints. Our results point to the difficulty of reinstating lost behaviors, and to the value of maintaining antipredator behaviors in conservation populations before they are lost.

A survey of current rehabilitation practices for native mammals in eastern Australia

Wildlife rehabilitation is common in Australia, with more than 30 mainly volunteer wildlife networks caring for thousands of animals annually. Here we report on a survey of 140 Australian wildlife rehabilitators that asked questions about their motivations, their methods of rehabilitation and their methods for release and post-release assessments. Most rehabilitators were motivated by animal welfare concerns and most animals coming into care were injured or orphaned wildlife. Most rehabilitators recorded each animal’s history, conducted a medical examination and briefly quarantined new arrivals; few conducted pre-release medical testing. Animal behaviour before release was a significant concern and >50% of respondents stated that animals exhibiting stereotypic behaviours were still released. However, there were no consistent criteria for the suitability of an animal for release, its release site, or which soft-release method to use. Fewer than 60% of respondents carried out post-release monitoring, which was typically <1 month, and only 40% could identify factors that contribute to release success. Predation hampers most reintroductions and is likely to reduce survival of rehabilitated wildlife, highlighting the need for strategies to reduce predation risk; 20% of respondents carried out antipredator training, though most in an unstructured way. The ability to carry out animal training, and monitor success was perceived to be limited by poor funding, poor access to monitoring equipment, little government support and time constraints. Researchers are encouraged to collaborate with wildlife volunteer networks in order to improve this potentially valuable conservation approach.

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

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.

Shyness and boldness in greater rheas Rhea americana Linnaeus (Rheiformes, Rheidae): the effects of antipredator training on the personality of the birds

The shy-bold continuum is an axis of behavioural variation for some species, but the consequences of shyness and boldness in antipredatory behaviour is unknown. Bold animals have the tendency to be predated first after release in comparison to shy animals, who naturally avoid the predators. Antipredatory training has been used to enhance the defence behaviours of naive animals by various researchers around the world. For greater rheas, Rhea americana (Linnaeus, 1758), this kind of study is pioneer. In this study we have investigated if there are relationships between personality and performance of greater rheas in antipredatory training. We also investigated if the training procedures influenced the behaviour of the birds when presented to novel objects. Fifteen zoo-borne greater rheas were studied and 16 personality tests were run, being eight before the application of antipredator training, and eight after the training. We presented to the birds four novel objects (ball, box, bag and person) and recorded their behaviour and the distance of the birds in relation to the objects. Results showed that the birds behave boldly before training and shyly after it. The antipredator training modified significantly the behaviour of the rheas, making them more careful about novel situations. Personalities affected the behaviour of the birds during antipredator training. The study of the animal personalities can be an useful tool in reintroduction programs since it helps to choose the animals with the highest chance of survival to reintroduce.

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

The antipredator training is a powerful tool now being used to help the reintroduced animals to recognise and escape from their predators. Testing the memory capacity of the animals after antipredator training is important to evaluate if the application of the training is worthwhile. A group of 15 captive-born greater rheas was studied at Belo Horizonte Zoo. Eight birds were antipredator trained and seven birds were not. After the end of the antipredator training sessions, we run four memory tests at 40, 55, 70 and 88 days after training was completed. The memory tests consisted of showing a predator model to the rheas and recording their behavioural responses. It was measured the capacity of antipredator information storage, the influence of the group size on the behaviour of the birds and the influence of the antipredator training on the elicitation of the correct behavioural responses of the birds when confronted by a predator. The results showed that the rheas retained predator recognition for almost three months, that the group size affected the responses of the birds (more defence behaviours expressed when tested alone) and that the antipredator training is essential to elicit the adequate antipredatory responses, since untrained birds behaved in a tranquil manner when confronted by a predator model. We concluded that antipredator training is worthwhile for future reintroduction programs for greater rheas, since their memory capacity is considerable.