Great reed warbler migration
The development of geo locators, or light loggers, has changed this, though, and now it is possible to track even as small birds as great reed warblers (Acrocephalus arundinaceu), weighing about 35 grams. In this project we hope to be able to map great reed warbler winter-and spring migration and also investigate sex differences in migratory strategies by using light logger technology.
Logging light data
Different arrival time
In 2008 we fitted 25 individuals with loggers and recovered 8, which is what could be expected from previous returning rates to the lakes without loggers. This data is yet to be analysed but look very promising. In 2010 we used an even smaller logger (1.8 grams) and could hence include females in the project. This is very exciting due to the prominent differences between sexes in arrival time at the breeding grounds. Here, one of the first returning great reed warblers is released from its light logger.