Diet and habitat use of moulting Greylag Geese Anser anser on the Danish island of Saltholm

Abstract

The diet and habitat use of moulting Greylag Geese Anser anser were studied at the recently established moulting site on the island of Saltholm, between Denmark and Sweden. Classification of the vegetation in the area most used by Greylag Geese during their moult showed that the geese selected low saltmarsh habitats which were richest in Common Saltmarsh‐ grass Puccinellia maritima and that dropping density was highly correlated with Puccinellia cover. Geese showed slowest step rates and highest peck rates in vegetation types rich in Puccinellia. Examination of faecal material confirmed that the geese fed almost exclusively on PuccineEia during the main moult period, despite its limited spatial distribution. Puccinellia maritima exhibited the highest levels of protein of any of the graminoid species present except for the belowground lower stem base of Sea Club‐rush Scirpus maritimus, which offers a nongrowing food resource which is difficult to extract and consume. The results of this study suggest that the statement that the “limited data available for moulting waterfowl indicate no active selection for proteinaceous foods; i.e., birds are selecting foods in proportion to their availability” does not hold for Greylag Geese moulting on Saltholm.