Feeding ”HOTSPOTS” and a management plan for the conservation of the common Guillemot
Our aim here is to determine the key feeding areas and migration routes of Common Guillemots (Uria aalge) colonies ranging from Bjørnøya (74 N) in the north to Isle of May (56 N) in the south. Such information is crucial for understanding predator-prey interactions and for targeting conservation efforts. Here we investigate this over a large geographic scale by synchronous deployments in 7 colonies across 3 oceans; Barents Sea, Norwegian Sea and North Sea. We will use a newly developed technique (Global Location sensing or GLS logging). The GLS loggers measure intensity of visible light every 60 s, and recorded the maximum reading within each 10 min interval. To estimate the spatial distribution of birds the loggers record ambient light, from which sunset and sunrise times are estimated from thresholds in light curves; latitude is derived from day length, and longitude from the time of local midday with respect to Greenwich Mean Time and Julian day. Compared to satellite telemetry these loggers are small (2.5g) and can be attached to the metal ring on breeding birds. Compared to other logging devices, they are inexpensive (c. 1000 NOK) enabling large samples to estimate the variance in feeding areas of birds from different colonies. The loggers are attached to breeding birds in colonies and then have to be recaptured the next breeding season.