Archaeological structures as factors affecting bird abundance and spectra in archaeological contexts from medieval and modern Belgium

The present study aims to evaluate the effect of archaeological structures in the preservation and recovery of bird remains, in particular by considering the overall shape, open or enclosed, of the structure. Indeed, hollow structures, sometimes of an enclosed shape that may be constructed in masonry, are supposed to have a protective effect on the fragile bones of birds. This is evaluated by considering different variables, such as the ratio of bird remains compared to those of the main domestic mammals used as meat suppliers, the number of bird taxa, or the identification rates for different types of archaeological structures. In a second step, once the impact of the type of structure is evaluated, the same variables are examined according to the social status, to verify their relevance to document this aspect. It transpires that the bird to mammal remains ratio is strongly influenced by the type of structure, as it is higher in enclosed structures. However, some open structures also deliver high bird ratios, in particular at high status sites. In contrast, the bird identification rate is lower in enclosed structures, but this is probably related to the recovery method. Finally, the number of taxa seems more affected by the social status of the consumers responsible for the accumulation of an archaeological assemblage than by the kind of archaeological structure the faunal assemblage was discarded into. This has implications for sampling strategies since open structures, when sieved, sometimes yield high bird to mammal ratios as well as a high number of bird taxa. Therefore, more systematic sieving of large samples of sediment should be applied not only to enclosed structures but also to open contexts such as refuse layers or floors, especially in sites of (potentially) high social status.