Monitoring continent-wide aerial patterns of bird movements using weather radars

Billions of insects, birds and bats use the aerosphere for migration, dispersive movements or foraging. This enormous movement of biomass plays a key role in ecological connectivity, yet monitoring aerial movements is technically very challenging. Individual tracking devices have been increasingly used over the last decade but these are currently only suitable for relatively large organisms, and the associated costs limits monitoring to a very small sample of the aerial animal community. Radars provide a tool for investigating and quantifying movement patterns for a wide range of flying organisms (birds, bats and insects), across communities and populations. However, research efforts in this field have often been local and uncoordinated. As a network of operational weather radars is continuously recording atmospheric conditions all over Europe, ENRAM (The European Network for the Radar surveillance of Animal Movement) has been recently established to explore the potential for coordinated, large-scale studies of the aerial movements of animals (Shamoun-Baranes et al. 2014). Here, we present the first outcomes of this collaborative research, and provide details on the visualization of a case study of mass migration of birds tracked using several national weather radars in the Netherlands and Belgium simultaneously. Finally we will also discuss the opportunities that a large sensor network can provide for movement ecology research at the continental scale.