Rocky areas, steep rock faces, and protosoils (immature soils) in mining site provide a habitat for very specialised animal and plant species. For example, steep rock faces formed from unconsolidated rock are important breeding sites for bird species that build holes, such as the Sand Martin, or wild bees. Escarpments provide nesting places for rock breeding bird species such as Eagle Owls, Jackdaws and Kestrels, while endangered plant species – such as the Carline Thistle or Catsfoot – can be found on rocky knolls and scree slopes. Open areas of protosoil are valuable habitats for numerous species of birds, grasshoppers, ground beetles, and spiders, for example.