The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.
This award will support a twenty-four-month research fellowship by Dr. Anna Nesterova (Vlasak) to work with Dr. Francesco Bonadonna at the CNRS - CEFE in Montpellier, France.
Orientation of colonial birds within a colony poses a puzzle to the current understanding of short-range navigation. The presence of many animals can obstruct familiar routes or any locally available cues, whether they are visual, auditory, or olfactory, making navigation especially challenging. King penguins (Aptenodytes patagonicus) are of particular interest to the studies of spatial orientation because they live in large and extremely densely populated colonies that can stretch over several kilometers. During breeding period each pair of birds reside within a fixed area of a few square meters. Mates alternate parental duties, and when one of the parents returns from a foraging trip it must find its mate in a crowded colony. While king penguins are famous for their vocal recognition of mates and chicks, the orientation based on vocalizations can take place only within several meters. It remains unknown how penguins proceed through a large colony to their residence areas. The objective of the proposed work is to identify mechanisms that allow animals to orient successfully in a crowded environment. Three non-mutually exclusive hypotheses are being evaluated: visual environmental features (landmarks) are important for homing; familiar routes are important for homing; and olfactory cues are important for homing. In the experiments, visual landmarks, familiar routes or olfactory cues are being manipulated, and the ability of penguins to find their residence area within a colony is tested. The view of visual landmarks is obstructed during the first experiment by fitting penguins with frosted goggles. In the second experiment, animals are released at novel locations around the colony in order to test the importance of familiar routes. In the last experiment, the availability of olfactory cues is controlled by temporarily plugging bird's nostrils. Increase in trips' duration and/or unusual trajectories during homing compared to the control condition (all cues are available) would suggest the importance for orientation of the cues being tested.
In addition to experimental manipulations, behavioral observations of movements within colony are used to investigate the use of visual landmarks. The observations are carried out during clear nights when some visual landmarks are available and overcast nights when no visual landmarks can be seen. The behavior of animals under these two conditions is compared. The results of this study are important for our understanding of the general short-range mechanisms that allow animals to navigate successfully in crowded environments.
