Do moulting Greylag Geese Anser anser forage in proximity to water in response to food availability and/or quality?

Flightless moulting Greylag Geese on the Danish island of Saltholm fed on P uccinellia maritima almost exclusively within 150 m of the coastline, despi te abundant equivalent food further away. This distribution pattern could t heoretically be Explained by two alternative (but not necessarily mutually exclusive) explanations: predation risk (since birds take to open water whe n disturbed) or variation in food quantity/quality. Above ground green part s of this plant showed consistently higher protein and lo cl,er fibre conte nt inland than on the coast, hence differences in food quality could not ac count for the difference in foraging distribution. However, in grazed plots , shoot density was greater at the coast than inland, resulting in an incre ase of 1.2-2.8 times the available green above-ground biomass. Hence, the g reater abundance of Puccinellia at the coast may contribute to the explanat ion. However within exclosures at the coast, Puccinellia shoot density was no different to inland areas, suggesting that some function of goose grazin g at the coast was involved in enhancing biomass there. It therefore seems likely that the greater food biomass at the coast is a consequence of geese feeding to within 150 m of the coast, though not necessarily the cause. Th e fact that the Greylag Geese fed throughout the island rc,whilst able to f ly but fed exclusively on the coast during sightlessness suggests that a pr edator escape mechanism could be the most important factor constraining the feeding distribution of moulting geese.