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
Audubon's shearwater likely, as yet another synonym of "dichrous". The case of the more distinct "bannermani", the range of which is parapatric to that of the Pacific "dichrous", is more complicated. It has for some time been proposed as a distinct species, Bannerman's shearwater ("P. bannermani"). In the absence of more recent data to investigate this claim, its status continues to be altogether unresolved, though the case for it being at least a distinct subspecies in the "bailloni" clade seems good. Audubon's shearwater The Audubon's shearwater ("Puffinus lherminieri") is a common tropical seabird in the petrel family. Sometimes known as the dusky-backed