Hot Birds Research Project

Predicting vulnerability to high temperatures using species-specific, mechanistic data, and assessing how this varies between species, is complex, time-consuming and expensive. As part of an ongoing project, we have been using the bird community in the southern Kalahari Desert, to investigate whether interspecific variation in heat dissipation behaviour could provide an index of vulnerability to high temperatures. We have been looking at a behavioural variable called pant50, which is the air temperature at which 50 % of observed individuals of a particular species are using behaviours that increase rates of heat loss, mainly focussing on panting behaviour because we know birds have to trade-off panting with maintaining adequate water balance. The ecological significance of the pant50 concept has already been highlighted in a number of species-specific studies and we have an extensive database of pant50 for ~ 50 species of birds in the Kalahari which reflect a large amount of variation between species. However, it is uncertain what this index can tell us about underlying physiological consequences and how changes in the physiology of birds relate to pant50. My Ph.D. focusses on validating this index by testing predictions that relate heat dissipation behaviours to underlying changes in body temperature, activity and hydration status in species that vary in pant50. If we are able to relate species-specific behaviour to underlying changes in physiological processes, and use assessments of this across communities we might be able to predict responses to climate change on a broader scale quicker and more efficiently.