The effect of rearing experience on subsequent behavioural traits in Hawaiian GeeseBranta sandvicensis: implications for the recovery programme

Abstract

SummaryThe risk of the NeneBranta sandvicensisbecoming extinct has been minimized by the release of over 2,000 captive-reared geese, but the population (now at 500) is yet to achieve a self-sustaining status. The majority of birds released have been reared in gosling-only groups, thus missing out on the opportunity to learn social and feeding skills from adults. In this paper we test the hypothesis that rearing experience affects the subsequent behavioural traits of Nene goslings. We raised 42 goslings under four conditions: a gosling group not exposed to adults, a gosling group exposed to adults from 16 days onward, three groups in view of “foster” adults for 14 days, and four groups reared continuously by parents. All birds were eventually released into an 8 ha pen where a flock of adult Nene roamed. The method by which Nene goslings were raised had a significant effect on dominance, flock integration, and vigilance. Parent-reared birds were dominant to and more vigilant than goslings raised without parents or goslings reared in sight of adults. Parent-reared birds also integrated into the adult flock sooner than other goslings. Growth rate and final body size were not affected by rearing regime (with or without parents or foster parents). In future, managers should provide goslings with as much “parental” experience as possible in order to equip them with appropriate skills to cope once released in the wild.

Survival and Recruitment of Captive-Reared and Wild-Reared Takahe in Fiordland, New Zealand. Sobrevivencia y Reclutamineto del Takahe Obtenido en Cautiverio y en Condiciones Silvestres en Fiordland, Nueva Zelanda

“…In addition, CR males may differ from WR males as a result of their early upbringing in groups without adults, in that they may be less dominant than WR males. This latter scenario has been reported by Marshall and Black (1992) in captive-reared Hawaiian Geese (Branta sandvicensis); parent-reared goslings were more dominant, more vigilant, and integrated earlier into the adult flock than those reared in gosling-only groups. The CR male Takahe have formed successful pair bonds at Burwood Bush Rearing Unit and on island reserves but in these areas they are not in competition with WR males for mates.…”

Genetic Analyses of Wild Populations of Hawaiian Geese Using DNA Fingerprinting

“…Unlike most Olinda birds, whose young often are reared by foster parents, the supplemental captive birds raise their own young. These parent-reared Nene appear to survive better in the wild (Marshall and Black 1992), perhaps contributing to the high survivorship of Nene in HVNP. In addition, much of the suitable lowland habitat for Nene occurs within HVNP, potentially increasing the recruitment of individuals from other populations.…”

Captive-rearing piping plovers: Developing techniques to augment wild populations

“…To date, our efforts have terminated when released juveniles disappeared from the general area of the release site. To evaluate the usefulness of captive rearing, information on postfledging movements, survival, and reproduction is critical [Page et al, 1989]. To justify a formal reintroduction effort using captive reared birds, breeding by released individuals needs to be documented.…”