Greylag geese (Anser anser) : crop selection and spatial distribution around Sörfjärden, Södermanland

Abstract: A rapid population growth in Greylag geese (Anser anser) has led to a conflict between geese and farmers due to the foraging geese in agricultural fields which causes damage to crops by trampling and grazing. Culling cannot always be used as a management tool due to protection of the species and temporal restrictions of hunting seasons. Therefore, non-lethal methods such as different scaring techniques and alternative reserved feeding areas, i.e. accommodation fields, have been developed to try to push them away from agricultural fields and pull them to these reserved feeding areas. To enhance the non-lethal management, more knowledge was needed about the geese such as crop selection and distribution patterns e.g. the selection of fields in relation to distance to roost sites. In this study the geese crop selection was estimated by compositional analyses over a three year period (March-October in 2010-2012) around Sörfjärden, Sweden. Moreover, the distribution of geese in relation to distance to roost sites was studied. The compositional analysis showed that the geese selected the acommodation field and grassland more than expected for 2010 and 2011, but that wheat was the top ranked crop in 2012. However, the selection of the accomodation field and grassland was more pronounced during early summer and the selection of grass fields´ declined during late summer. The geese shifted to cereals such as wheat (Triticum spp.), barley (Hordeum vulgare) and pea (Pisum spp.) in late summer, probably because of higher availability due to the harvest and waist grains on the stubble fields. No significant results were found on geese distribution of distance to roost site, due to clumped distances to roost sites in the study area. In conclusion, accommodation fields are a good non-lethal method to ease the grazing pressure on agriculture fields especially during early summer in Sörfjärden.