Does size matter? Maximising nutrient and biomass intake by shoot size selection amongst herbivorous geese

The selectivity of Greenland White-fronted Geese Anser albifrons flavirostr is feeding on Timothy Phleum pratense hayfields in Iceland during their spr ing staging was studied in three fields of different shoot density (high, m edium and low) and discussed in the context of optimal foraging. Biomass an d nitrogen content of the Phleum laminae (leaves) taken by the geese were a nalysed and correlated to lamina length. In all fields the geese were highl y selective for the larger laminae, ignoring shorter ones. Because the qual ity (nitrogen content) of the laminae decreased only slightly with increasi ng lamina length, the geese maximised their intake per peck by only taking the largest laminae. This study suggests that, even at high peck rates, her bivorous geese are capable of selecting most profitable bite sizes at a fin e grained scale.