Wintering geese and swans foraging on unharvested sugar beets: an emerging problem

Farmers in south-east Denmark experience increasing problems with foraging barnacle geese on their crops, particularly affecting winter wheat, seed grass, and winter rape. Sugar beet waste is often exploited by geese and swans, and in recent years barnacle geese have adapted to foraging on unharvested sugar beet fields as well. Sugar beet biomass measurements and bird counts show that geese and swans cause damage to unharvested sugar beets. Economic loss caused by geese and swans in eight surveyed sugar beet fields was estimated at less than 1% of the fields’ value. Both economic loss and area damaged were correlated with abundances of geese and swans. In total, 10% of the sugar beet fields in the study area were utilized by geese and swans before harvest. Hence, foraging on unharvested sugar beet by geese and swans is not considered a widespread problem, but there are indications that the phenomenon is increasing. Particularly barnacle geese may become a more serious problem due to their occurrence in large flocks and high degree of mobility. • Geese and swans forage on unharvested sugar beets in autumn in Denmark • Since 2018 numerous barnacle geese adapted foraging on sugar beets as well • So far yield losses are local and minimal • The amount of damage at field level scales with abundances of geese and swans • If barnacle geese consistently switch to sugar beet, management may have to be coordinated