A million birds: more than half the world’s Manx Shearwaters breed in Wales

A Manx Shearwater among the flowers, photograph by Chris Perrins

Christopher Perrins (Department of Zoology, University of Oxford, UK) and colleagues have published open access in the annual journal Seabird on a census of Manx Shearwaters Puffinus puffinus on three islands off the coast of Wales.

The paper’s abstract follows:

“We present the results of a census of the Manx Shearwaters Puffinus puffinus nesting on the three Pembrokeshire islands of Skomer, Skokholm and Midland (formerly Middleholm), Pembrokeshire, undertaken in 2018. The breeding population estimates were largely in line with those made in 2011–2013, but differed markedly from 1998; this difference seems to be due to the different methods used in 1998 rather than any marked change in population size. Despite attempts to refine the estimation of response rate to call playback, the error of the population estimates remains large, illustrating the logistical and analytical challenges of making seabird censuses using call playback. Nonetheless, the population estimates are large and the spatial distribution of occupied burrows is consistent between censuses, and thus Wales may hold more than half of the world’s breeding population of Manx Shearwaters.”

Reference:

Perrins, C., Padget, O., O’Connell, M., Brown, R., Büche, B., Eagle, G., Roden, J., Stubbings,^, E. & Wood,^, M.J. 2019.  A census of breeding Manx Shearwaters Puffinus puffinus on the Pembrokeshire Islands of Skomer, Skokholm and Midland in 2018.  Seabird 32: 106-118.

John Cooper, ACAP Information Officer, 26 November 2020