Above and below are some images of Manx Shearwater, most of which passed within a couple hundred yards of the island. 95% of the worlds' population of Manx breed around the UK and can be seen easily from most Cornish headlands between spring and autumn.
The Manx image below is an odd one and still cannot quite work out what's happened here? Presumably the shutter speed was not quite fast enough?
The image below is a Balearic Shearwater in heavy moult. Balearics are a regular sight in Cornwall in the summer months though their sightings mask their true rarity as a world breeder. No more than 11,000 pairs breed in the Med and these numbers are in decline.