Grassholm

Grassholm is a small (0.1072 km²) uninhabited island off the coast of SW Wales, UK. It was bought by the Royal Society for the Protection of Birds in 1947, who continue to manage it.

Famous for its large gannet colony, numbers of this iconic species were severely negatively impacted by the 2022 outbreak of high pathogenicity avian influenza. Drone surveys indicate the breeding population dropped from 34,491 pairs in 2022 prior to disease outbreak to only 16,482 pairs in 2023.  Grassholm also supports breeding common guillemots, European shags, razorbills, black-legged kittiwakes, great black-backed gulls, lesser black-backed gulls, herring gulls and European storm petrels.