The Guano Covered Island of Grassholm By Kaushik Tuesday, September 02, 2014 Animals, Islands, Travel, U.K. No comments Grassholm is a small uninhabited island, just 200 meters across, located 13 kilometers off the southwestern Pembrokeshire coast in Wales. This tiny island is home to one of the largest colonies of gannets. During the breeding season, from April to September, ..