Puffin - 2003-07

Common offshore around western Pembrokeshire between late March and late July each year, but rarely seen outside this period, they congregate in large rafts close inshore near their breeding colonies in the spring and early summer months and socialise around their breeding colonies each evening.

Puffins are mostly confined to offshore islands free of predators, particularly rats. They nest in burrows on steep slopes in sometimes very dense colonies.  The principal colonies are on Skomer Island, including Middleholm, and Skokholm with small populations on the Bishops near Ramsey, on St Margaret’s Island and at Stackpole Head where they nest in sheer cliff sites.

Numbers in the past were clearly very much higher than they are now and for example it was estimated that 500,000 to 700,000 pairs nested on Grassholm in the  1890’s,  a figure disputed by modern analysis which suggested that around 200,000 pairs would be more realistic.  Whatever the actual figure, the density was clearly much higher than in today’s colonies and on Grassholm there are still remnants of the collapsed burrows testifying to this. This colony was more or less deserted during the 1920’s and it has been suggested that the birds relocated to Skomer and Skokholm, although it is not clear how that assumption was made. There were also apparently big colonies on Caldey and Ramsey in historic times, before rats devastated them.

Mathew (1894) made the observation that they were undoubtedly the most common bird in Pembrokeshire with huge colonies on Skomer stating “ there is scarcely a yard of ground free of them” and Lockley et al (1949) thought that around 50,000 pairs were breeding on Skomer and 20,000 on Skokholm. There were clearly many more birds present than there are today. 

The population estimates which have been made since the 1950’s on both Skomer and Skokholm have been consistent in suggesting that around 9,000 to 10,500 pairs may breed there.  Estimates are however subject to substantial inaccuracies because it is not possible to count burrows, as both rabbits and shearwaters breed on both islands in abundance, and estimates have tended to be done by extrapolation of detailed studies in one small part of the islands.

Consequently, in an attempt to provide greater consistency in counting and to provide comparative long term data of population trends, all counts of birds since the 1980’s have concentrated on the maximum attendance by adult birds in the spring. The spring counts in 2003-2007 of around 10,800 individual birds on Skomer and 4,800 on Skokholm  suggests a rather similar breeding population to the 1985-87 Seabird Colony Survey estimate of a total breeding population of  about 10,600 pairs  on the two islands.

Stephen Sutcliffe

Fieldwork 2003-07 (based on 490 tetrads)

Red = breeding confirmed = 4

Orange = breeding probable = 2

Yellow = breeding possible = 0

Total tetrads in which registered = 6 (1.2%)