Corvus mondedula spermolegus
Common resident, except at Skokholm and Grassholm, where only a spring migrant at same time as Rook. Breeds on cliffs and in ruins, etc, inland. A writer in the Field, 2 June, 1860, noted that it bred in burrows at Skomer; it still does this – in sea-bird burrows on the edge of the cliffs.
Pembrokeshire Avifauna 