St Levan common species such as northern gannet ("Morus bassanus"), Manx shearwater ("Puffinus puffinus"), common guillemot, ("Uria aalge") and razorbill ("Alca torda"), as well as rarer birds such as Balearic shearwater ("Puffinus mauretanicus") and Cory's shearwater ("Calonectris borealis"). The headland of Tol-pedn (or Gwennap Head) is favoured by birdwatchers and many travel the length and breadth of Britain to track rare seabirds. Some of the butterflies that can be found on the coast include grayling ("Hipparchia semele"), silver-studded blue ("Plebejus argus"), small pearl-bordered fritillary ("Boloria selene") and wall ("Lasiommata megera"). There is also a day-flying moth, the thrift clearwing ("Synansphecia muscaeformis"); the
Chagos Marine Protected Area Chagos are considered to be of international importance. The archipelago harbours eighteen different species of breeding birds and ten of its islands have been designated as Important Bird Areas (IBAs) by Birdlife International, making the region the most diverse breeding seabird community in this tropical region, though the presence of human-introduced rats on several of the other islands severely hinder seabird nesting on these. Five species are considered to be breeding in internationally significant numbers: the sooty tern ("Sterna fuscata"); the brown and lesser noddy ("Anous stolidus" and "Anous tenuirostris"); the red-footed booby ("Sula sula") and the wedge-tailed shearwater ("Puffinus