Thermal Physiology, Behaviour and Energetics of Australian Birds
A key problem of survival for small mammals and birds is managing the opposing risks of starvation and predation. Foraging increases energy intake but it also increases the likelihood of encountering or being detected by a predator. Conversely, the avoidance of predators can result in a loss in food consumption and increased risk of starvation. This trade-off is fundamentally driven by a need for energy (and other nutrients, especially protein). By using torpor, a temporary and controlled downregulation of body temperature and metabolic rate, some animals can greatly reduce resting energy use, allowing for reduced foraging need and stronger anti-predator behaviours. However, torpor is widely hypothesized to increase the risk of predation when animals are resting, because low body temperature is associated with loss of mobility and responsiveness.
Heightened risk of predation is widely assumed to restrict birds from using torpor, however, there has been very little research to test if birds using torpor are less responsive to external cues. Additionally, there has been no research linking energy saving torpor bouts and the potential for reducing the risk of predation associated with foraging activity in birds. Therefore, my thesis aims to describe natural patterns of body temperature regulation in wild passerine birds and experimentally test how torpor and resting energy need influences foraging decisions. Experimentally testing the connection between torpor and risk of active and rest-phase predation will help establish the costs of torpor and the effect of energy need on anti-predator behaviours.
Dr Chris Turbill, A/Prof Ben Moore, A/Prof Justin Welbergen