Harold Grenfell very kindly provided me with a copy of one of his images of the Northern Mockingbird that was present on the inner Worm's Head between 24th July and 11th August 1978. The reasons this record was placed in category D were because the bird turned up near to a port and because it was deemed too early for a true migrant. The fact that Swansea is hardly used by trans-Atlantic traffic seems to have been missed and furthermore I suspect more trans-atlantic ships pass Cornwall and possibly even Essex, these being the counties of the only two category A British records. Also the dates for the two category A records are hardly typical for trans-atlantic vagrants, so the decision seems a bit harsh in my opinion. Acceptance category aside, it's the only Glamorgan record of an American passerine to date!