Foraging behaviour in chick-rearing Razorbills
Stora Karlsö is a 2.5 km2 island located in the western Baltic Sea; a major auk breeding site, with approximately 12 300 pairs of Razorbill, 15 700 pairs of Common Guillemot, and breeding populations of several other seabird species. In this study, Natalie Isaksson, Tom Evans, Susanne Åkesson and Olof Olsson investiged the foraging behaviour of Razorbills during the breeding season (the chick-rearing period), using a combination of global positioning system (GPS) and time-depth recorder (TDR). Five GPS tracks and nine TDR logs were retrieved from 12 Razorbills, and 7399 dives were analysed. The results showed that aside from dive shape, foraging behaviour was consistent with that reported at other colonies of Razorbills. The authors suggest that inconsistency in dive shape may be due to a bimodal foraging strategy, local prey behaviour or competition with the Common Guillemot Uria aalge.
To the paper: Foraging behaviour of Razorbills Alca torda during chick-rearing at the largest colony in the Baltic Sea in Bird Study.