In this project, PhD candidate Tanja Van de Ven focuses on the effects of high temperature on the breeding performance of the southern yellow billed hornbill Tockus leucomelas in the southern Kalahari. I aim to identify whether temperature thresholds exist above which the care for offspring is impacted by the effects of high temperatures on the parent birds. Hornbills are cavity nesting breeders, whereby the female seals herself inside a nest cavity where she cares for the chicks. During this period the male is solely responsible for food provisioning for the entire family which increases his energetic cost. Observations of the male hornbill show increased selection of shaded microsites when ambient temperatures increase. These shaded sites limit the bird’s foraging opportunity and this in turn leads to lower nest provisioning rates. I observed that with high ambient temperatures (>35°C) the male birds decrease nest provisioning rates, but the proportion of prey consumed by the male remains the same. Hornbill chicks hatch asynchronously and food allocation to the chicks is done by the female inside the nest. Data on daily body mass gain suggest that the first born chick receives a constant food supply irrespective of ambient temperature. The daily body mass gain of the second and third hatched chick is however heavily influenced by ambient temperature, as well as the female’s body condition.