Climate-controlled chambers for the study of physiology and behaviour.

Wild birds experience a broad range of temperatures. These fluctuations have a profound influence on their lives. However, studying this influence is not an easy task, because in the field, variation in temperature is not independent of other variables (such as the day length), and in the laboratory, experimental manipulation of ambient temperatures over the natural range requires specialist equipment. We are applying for money to purchase such equipment that will allow us to vary temperature and day length independently from each other and from other factors. This equipment will consist of four chambers in which we can house birds either in cages, or in free flight. The four chambers will be independently controlled, so we can simultaneously have different groups of birds in different conditions. This equipment will then be used to ask a number of scientific questions. Some of these questions relate to the role of temperature in preparing animals for the changing seasons. We know that day length is an important signal in this preparation, but the role of temperature (which changes in concert with day length in nature) is still very much unknown. Other planned studies will address questions about how an animal responds to being in a situation where its energy reserves are limited. When it is colder, more energy needs to be spent on staying warm, and therefore more energy is required. We will study how this increased need for energy influences decisions animals make about what to eat and when. Understanding how animals respond to differences in temperature is also very important if we want to understand the potential impacts of global climate change on animal behaviour and therefore on their populations. This equipment will be unique in the UK and will allow us to ask questions that we have not been able to answer before.

The equipment will consist of four climate-controlled and Home Office-licensed chambers to house birds. A number of research projects will be conducted using this equipment, all of which crucially need to be able to closely control the environmental temperature in which the birds are held. In some of these experiments, photoperiod will be manipulated independently of temperature (and vice versa) in order to tease apart their respective roles in triggering seasonally-controlled changes in physiology and behaviour. Two sets of experiments will especially focus on effects on breeding status and on food-hoarding behaviour. In another group of experiments, temperature will be manipulated as a tool to change animals' energetic states. Animals with limited energy reserves are likely to behave differently in a foraging situation, possibly taking more risks or changing their metabolism. The risks can take the form of exposure to possible predators, or eating food that may carry a cost with it (because it is slightly toxic, for example), while the metabolic changes can involve active or passive hypothermia. Only by closely manipulating temperature can we experimentally control energetic state of the animals and examine its effect on these kinds of decisions and processes.