Alca torda britannica
Mathew describes it as a common summer resident, but less numerous than Guillemot or Puffin, and mentions the following breeding stations: Caldey, St Margaret’s, Skokholm, Skomer, Grassholm, Ramsey and various mainland cliffs. Breeds today in suitable sites from Cemmaes Head to Caldey. Decreased during the recent war, probably because of oil-pollution.
Pembrokeshire Avifauna 