Bob Bullock very kindly emailed me several images depicting third and fourth-year NORTHERN GANNETS resembling adult Black-browed Albatross in appearance. The first three images depict the bird seen from the ferry between Gills Bay and St Margaret's Hope on Friday 25 September - the same bird I had seen on Thursday 24.
These individual Gannets are a major pitfall both on pelagic trips and seawatches as they superficially resemble Black-broweds; a very similarly plumaged bird was seen on one of the Scillonian pelagic trips in the late 1990's (Lee G R Evans)