Flight Physiology of Migrating Northern bald ibises

The research project will capitalize on a Northern Bald Ibises (NBI) conservation project to collect physiological data on these birds that will shed light on the energetics and energetic decisions made during and after migratory flight. In the proposed project, the authors plan to use the techniques of hand-raising NBI in Austria and physically leading them over a migration route to a wintering area in Northern Italy to document the in-flight physiology of a migratory bird. The close relationships between the birds and their human foster parents will allow us to collect these data with a minimum of disturbance for the birds. Key parameters will be measured in blood chemistry to document the individual energetic condition, fuel use and the endurance capacity. These will be compared with individual flight behaviour and metabolism assessed with the doubly labelled water method. Non-invasive monitoring of adrenal activity will complement the blood chemistry and the metabolic measurements. Finally, body mass and subcutaneous fat changes will be monitored as cross-indicators of tissue use. The goals are to determine whether changes in blood chemistry parameters are used by the birds to terminate individual migratory bouts and, whether the degree of change predisposes an individual shift from a catabolic to an anabolic state. The experimental set up will allow the researchers to carry out both fatiguing and non-strenuous flight bouts in one year. This will allow us to document extremes in the analyses of physiological parameters and flight duration. In a second season, the spontaneously occurring energetic and physiological set points for migratory bouts will be investigated. This will be the first case of a study combining blood parameters, endocrine analyses and energetic measurements in free-flying migrating birds. The NBI is a globally endangered species that became extinct in European during the middle ages. Information about their migratory physiology is essential to the establishment of migratory traditions with human lead migration.