Bird bone taphonomy from the inside out: the evidence of gull predation on the manx shearwater puffinus puffinus.
Dale Serjeantson, Brian Irving & Sheila Hamilton-Dyer

ABSTRACT: During a visit to the island of Skomer, South Wales, UK, in July 1992, we saw many dead manx shearwaters, assumed killed by great black-backed gulls Larus marinus, with distinct pattern of damage to the carcass. In this paper we describe and illustrate the traces of damage seen on the bones and the sequence of disarticulation of the carcass. The gulls make a distinctive gash in the sternum, and some less distinctive breaks in some other bones. The first part of the carcass to become disarticulated is the head, which has often been turned inside out by the gull. This is followed by the legs, which become detached from the body separately. The two wings and pectoral girdle remain in articulation longest, after all the flesh has been removed.

Past work on bird bone taphonomy has used the evidence of surface preservation of the bones and the ratios of the main anatomical elements. Though the Skomer birds provide some support for the hypothesis of Ericson that birds from natural deposits will be represented mainly by their wing bones, this may be an oversimplification. The anatomical distribution of two small archaeological groups is considered, from the Udal North, Hebrides, Scotland, and from Launceston Castle, Cornwall, England. The context of both suggests an anthropogenic origin, but anatomical distributions are very different.

Measurements of the humerus, ulna, and tarsometatarsus are given in Appendix 1. The tarsometatarsus length is compared with an earlier sample from the same island.