Do seabird colonies function as information centres? A study with northern gannets Morus bassanus

In 1973, Ward and Zahavi suggested animals could locate prey patches using a process known as information transfers by following previously successful foragers from their colonies: Although several reviews refuted early support for information transfers (Richner and Heeb, 1995, Mock et al., 1988) recent evidence has emerged amongst communally roosting juvenile ravens Corvus corax (Wright et al., 2003, Marzluff et al., 1996) and hooded crows Corvus cornix (Soneraud et al., 2001). Despite this, such evidence remains scarce within colonial breeding species including pelagic seabirds. Here I use modern analytical methods (Stable isotope analysis and GPS loggers) alongside in-situ observations to investigate information transfers in northern gannets Morus bassanus, where provisioning activities, extensive colonial occupancy and conspicuous sky-pointing behaviours may provide birds with opportunities to locate of prey patches by following successful neighbours from the colony. However, my results suggest that these strategies were, at best, rare as (1) birds rarely followed neighbours from the colony (2) neighbours generally commuted towards and forage in different regions and (3) stable isotope ratios in plasma suggested that neighbours forage in different prey patches. Instead it appears that gannets may use a form of memory-based network foraging by consistently commuting into a favoured region before using at-sea information to locate fine-scale prey patches found therein. I discuss results in regards to reasons why gannets may not utilise information provided by their neighbours, several alternate uses of social information within breeding colonies (information halos and non-breeders) and the benefits gained from using a form of memory-based network foraging.Faculty of Scienc