Last month I took the opportunity to try and film the behaviour of some of the juvenile Lesser Black-backed Gulls of our IJmuiden Forteiland project that are fitted with a GPS logger.
Apart from storing data such as the date, time, speed, and height, their loggers also measure the acceleration. This is done in three axes:
- Surge (movement forwards)
- Heave (movement upwards)
- Sway (movement sideways)
This data is then shown in a graph in which surge is shown as a red line, heave as a green line, and sway as a blue line.
If the bird changes direction slowly, the lines will only show a slight change; if the bird changes direction quickly, the lines will show a large change.
When studying these graphs, specific movements can be detected such as flight (flapping or soaring), floating, standing, walking, pecking, and so on.
The best way to learn how to ‘translate’ these graphs into behaviour without having seen the bird is to try and film individuals and match the footage with the data from the logger.
This is obviously quite challenging but I managed to do this on two occasions.
Here is a small sample of juvenile Lesser Black-backed Gull Green YDDD with logger 7009 flying up in the colony, soaring along the water line and landing:
Here is part of that video shown in the application of the University of Amsterdam in which it is matched with the GPS data (many thanks to Dr. Judy Shamoun-Baranes for giving me permission to publish this data here):
Note the changes in acceleration during flight (especially on the green heave axis) and the large movements along all 3 axes when it lands).
Here is a screenshot of that video (click for a larger view):
It is great to be able to contribute to this project in this way, and to study the behaviour of birds in such a scientific way.
About the project
The tracking study is part of an ongoing collaboration between the University of Amsterdam UvA (Dr. Judy Shamoun-Baranes) and the Royal Netherlands Institute for Sea Research NIOZ (Dr. Kees Camphuysen).
The study is being conducted within the project “Interactions between birds and offshore wind farms: drivers, consequences and tools for mitigation” funded by NWO Applied and Engineering Sciences Open Technology Programme, Rijkswaterstaat and Gemini windpark.
The tracking study will provide complementary information on the movement patterns of gulls breeding along the North Sea coast, with similar objectives to the studies conducted on Texel and Schiermonnikoog.
The main aim is to identify intrinsic and external drivers of movement from fine scale flight behaviour to seasonal migrations. While adult gulls from other colonies have been tracked since 2008, little is still known about the daily movements and flight behaviour of juveniles and how this differs from adults.
This study will contribute to our knowledge on how juvenile birds develop their foraging and migration strategies and how their flight behaviour differs from adults.
If you come across any of our gulls from the IJmuiden Forteiland project, please let us know. Feel free to include me on the e-mail: gulls at vankleinwee.com.