The odd case of Eidolon - a long-distance migrating flying fox
Animal migrations are a hot topic in the context of global change and the recent wave of technical developments of tracking methodology has given this field of research a much-needed boost. Until recently, the relatively heavy weight of satellite and GPS tracking devices remained a limiting factor for the study of the movements of many, especially small, animal taxa.
Wandering species often cover large distances, frequently crossing country borders. This means they depend on a multitude of ecosystems and suitable stopping sites - making them particularly vulnerable. Bats and especially flying foxes are moving into the focus of attention for two very different reasons in this context: 1) because their habitats overlap with those of us humans and thus they have a particularly strong transmission and dispersal potential for human-relevant diseases, and 2) migrating flying foxes are crucial ecosystem service providers as pollinators and seed dispersers, far outcompeting any other animal group.
The launch of our new tracking technology ICARUS will finally allow us take a large step towards filling in the blanks regarding the migratory behaviour of the Straw-coloured fruit bat, Eidolon helvum, the most extreme long-distance migrant of all flying foxes. With this knowledge we will not only better understand the evolution and drivers of migratory behaviour (why is this behaviour so unique among bats?), but also gather crucial knowledge about the effects human-induced change of the landscapes have on the flying foxes (threats facing a vulnerable migrating species) as well as the effect the flying foxes have on the landscape (ecosystem services). In order to properly weigh all these aspect against each other and put them in context with the migratory behaviour we need detailed movement data from a large number of individuals over a long time period, at least one year (covering one full migration cycle). Before ICARUS we were only able to collect high-resolution data of nocturnal foraging movements, but not from migratory movements. The results of this research not only have the potential to truly change and expand our understanding of animal migrations, but also to provide essential fundamental knowledge for the fight against global zoonotic disease.