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Avian flight: Integrating experiments with aerodynamic theory

Final Report Summary - AVIAN FLIGHT (Avian flight: Integrating experiments with aerodynamic theory)

In this project we investigated the aerodynamic consequences that molt and carrying tracking devices, such as geolocators, had on small passerine birds. In a paper already published in 'Methods in Ecology and Evolution', we showed that the drag of tracking devices could have effects similar to the weight of the devices. This was significant because the vast majority of guidelines that described how to properly use these devices ignored the effects of drag. We also worked with several groups producing geolocators in both Europe and the United States of America in order to help them minimise drag and we are at present planning a follow-up project.

Our research on the effects of molt was not yet published by the reporting time, nevertheless we were able to quantify the effects of both natural and experimental molt on the aerodynamic wakes generated by a small migratory songbird. This was a first step in understanding the diversity of molting strategies found in avian species. Once these strategies were understood, we could also begin to understand the evolution of avian life history strategies. We would then ultimately be able to use these data to create theoretical models that would better account for increased energy use and decreased flight ability during molt.

We also initiated a comparison of Old World and New World migration systems using geolocators and collected data which would be used to compare bird and bat flight. Furthermore, we collected data for a pilot project on the aerodynamics of landing behaviour in small birds. Members of the Lund laboratory were able to witness the implantation of a heart rate transmitter, and learned a technique for repeatedly attaching heart rate transmitters that the fellow developed. The fellow also shared her knowledge of statistics with other members of the laboratory during her tenure at Lund. In turn, she was trained in three-dimensional particle image velocimetry (3D-PIV) and kinematic techniques and learned how to use Matlab. Perhaps more importantly, she established lasting connections with many Europeans, including migration researchers who were not based at Lund. We anticipated that these connections would result in numerous future collaborations.

The additional products and outcomes of this project were as follows:
1. the Marie Curie fellow was invited for interviews at several universities and accepted a position as an assistant professor in the department of natural sciences at the University of Michigan-Dearborn. For further details see
2. the fellow presented papers at three scientific conferences during her tenure at Lund, including one where she introduced a symposium that she organised. The topic of the symposium was 'Integrative migration biology.' It was funded by the National Science Foundation (NSF), published in 'Integrative and Comparative Biology' and brought together established migration researchers from the United States with established researchers in Europe. Perhaps more importantly, it attracted a large number of graduate students and post-docs who were able to interact with each other and with established faculty members who worked on migration. The interactions during this symposium and the related social activities resulted in several new collaborations between researchers in the United States of America and in Europe.
3. the fellow also participated in several internal conferences, as well as in a workshop in Leiden designed to facilitate integration of field data with theoretical models and in a workshop in Radofzell designed to facilitate coordination amongst migration researchers.
4. the fellow shared her knowledge of methods used to measure metabolic rate, including the proper use of heart rate transmitters, at Lund's migration biology PhD course. This course was taught to 40 graduate students from 22 different countries.

Finally, the paper 'Mechanistic principles of locomotion performance in migrating animal', by Hedenström A., Bowlin M., Nathan R., Nolet B. and M. Wikelski, was already published as a result of this fellowship; several additional papers were in preparation by the time of the project completion.