Random time-activity budgets in captive Southern Ground Hornbill Bucorvus leadbeateri

Abstract

Introduction: The conservation status of the Southern Ground Hornbill (Bucorvus leadbeateri) is vulnerable on the IUCN Red List. The Mabula Ground Hornbill Conservation Project (2011) and Southern Ground Hornbill conservation in general aim to increase the number of hornbills through five main techniques: (1) supplemental feeding, (2) double clutching, (3) alternation of chicks, (4) group augmentation and (5) chick fostering. Numbers are threatened directly by habitat loss, hunting and international trade, and indirectly by group size (through the Allee effect) and communal breeding. Furthermore, the species has a highly K-selected life-history pattern. Captive breeding of this bird can potentially increase the population size twofold because both eggs laid are guaranteed a chance of survival, whereas in the wild only one egg is likely to survive. Time-activity budgets in birds can be used to illustrate reproductive effort. Time-activity budgets are known for Southern Ground Hornbills from wild birds in the Kruger National Park and from one captive pair (Johnson B 2004, personal communication). We compared the time-activity budgets of captive Southern Ground Hornbills in the Johannesburg Zoo with randomly expected behaviour of the same birds and previously studied birds.