ROSELAAR CS (2012) The origin of Dutch Puffins Fratercula arctica . LIMOSA 85 (1): 13-21.

The national bird skin collection of the Netherlands, housed in the National Centre for Biodiversity ncb Naturalis in Leiden, contains 186 skins and mounts of Puffin Fratercula arctica. Of these, 94 were found washed ashore in the Netherlands during 1835-2010, and 84 were from the breeding grounds, especially from Iceland. Wing length (maximum chord), bill length (culmen without cere) and bill depth (at deepest point, without cere) of all birds were taken before an audience in the LiveScience hall of ncb. Wings of the Dutch sample ranged from 132 to 176 mm, pointing to the occurrence of several subspecies. The large variation is however also due to the presence of juveniles, which were found to have an average wing length 13 mm shorter than adults. Most birds had washed ashore in winter (table 1). None of the adults was in wing moult, but of five immature birds from June four were in simultaneous flight-feather moult. Comparison of wings from the Netherlands with those in ncb from the breeding grounds (fig. 1) shows that 14% of the birds of the Dutch coast belong to nominate arctica (table 2), 86% to grabae (including birds from southern Iceland - fig. 2). No bird with measurements suggesting the high-arctic subspecies naumanni was found. Because bills of adult winter birds are smaller than those of breeding birds and also juvenile and immature birds have small bills (table 3), bill measurements were not helpful to assess the origin of non-breeders. Measurements of European populations from the literature (table 4-5, summarised in fig. 3) show that size variation is not strictly clinal, but that two parallel clines occur, in each of which size increases from southern colonies to northern ones or from warmer August water temperatures to colder ones: an 'Atlantic' cline (western British Isles, Shetlands, Faeroes, Iceland, Bear Island) and a 'continental' one (France, eastern Britain, coastal Norway) (fig 3). Whether these two clines are due to genetic or to ecological differences has to be worked out. Because of the abrupt changes in wing and bill measurements over a short distance between southern and northern Iceland and (within Norway) between Rogaland and Runde Island, recognition of the smaller subspecies grabae and the larger nominate arctica is maintained, as is naumanni.

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