Field naturalists have searched across Clare Island for animal groups ranging from the microscopic to birds and mammals. Many more species have been found since the original survey a hundred years ago, due to the availability of modern methods, which greatly add to our knowledge of the biodiversity of Clare Island. The lists of species featured here include some new to the island, some new to Ireland and some new to science. This volume signals the need for further field work and taxonomic research to track biodiversity changes arising from human activity. Land and freshwater fauna is the tenth volume in the New Survey of Clare Island series, which seeks to build on the pioneering work of the first Clare Island Survey (1909–11), the most ambitious natural history project ever undertaken in Ireland and the first major biological survey of a specific area carried out in the world.