Behavioural trait assessment as a release criterion: boldness predicts early death in a reintroduction programme of captive‐bred swift fox (Vulpes velox)

Abstract

Reintroduction of captive-bred animals is a key approach in conservation attempts for many endangered species, however, post-release survival is often low. Rearing conditions may be unlike those encountered upon release and the animals may not have had experiences necessary for survival in the wild. Animals may also habituate in captivity to stimuli that may pose a danger after release and/or there may be selection for behavioural traits, in particular reduced fearfulness, that may not be suited for the wild. Here, variation in boldness was assessed in captive-bred swift fox (Vulpes velox) and tested for influence on survival after release. Radio-tracked individuals that died in the 6 months following release were those judged previously as bold.In the presence of novel stimuli in captivity, they had left their dens more quickly, approached more closely to the stimuli and shown more activities indicating low fear than did those that survived. These individuals were less suited for release. Future selection of release-candidates on the basis of behavioural variation should enhance the success of reintroduction programmes.

Diverse societies are more productive: a lesson from ants

“…In solitary animals, selection acts on individual phenotypes, e.g. high aggression in Ural owls [43] or low boldness in swift foxes [44]. Social species, however, are under multi-level selection [10].…”

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

“…Boldness scores, calculated according to BREMNER-HARRISON et al (2004), showed that, before antipredator training sessions, rheas were bolder than after. These results were more evident for rheas belonging to trained-group two, and less evident for trainedgroup one (which behave shyly before and after antipredator training), although this group displayed shy behaviours more intensively after the training sessions.…”

“…According to this index, trained-group one showed more shy than trained-group two, avoiding to approach the novel objects; meanwhile, during antipredator training, it was trained-group one who behave boldly. In the calculation of the boldness score proposed by BREMNER-HARRISON et al (2004), fear behaviours are multiplied by zero, while bold behaviours are multiplied by two. Maybe these different weights given to the behaviour categories are responsible for this kind of antagonism.…”

“…BREMNER-HARRISON et al (2004), studying swift-foxes Vulpes velox (Say, 1823) in the United States, discovered that the bold animals presented mortality rates significantly higher than the shy ones, and that the bold individuals die faster after the release if compared to the shy individuals.…”

“…The number of registers of each behaviour was counted and used in the calculation of the boldness scores, according to BREMNER-HARRISON et al (2004): the total number of fear behaviours was multiplied by zero; the total number of shy behaviours was multiplied by one; and the total number of bold behaviours was multiplied by two. For each group, the totals of the multiplication were summed and the numbers achieved were the boldness score values -the bigger the value, the bigger the boldness of the group (Tab.…”