Small mammal deposits in archaeology : a taphonomic investigation of Tyto alba (barn owl) nesting and roosting sites.

Small mammals have often been utilised as indicators of past environments. Before palaeoecological assessments can be made, investigations into the origin and mode of deposition are carried out. Many small mammal accumulations are predator-derived, and in order to take account of predatory bias in these deposits, it is necessary to identify the predator. Several methodologies have catalogued patterns of bone modification from dietary waste of modern predators, for comparison with taphonomic features found on archaeological assemblages of small mammals. The majority of this research has concentrated only on the adult age range from these predators. However, data from owls have shown that younger individuals are often responsible for more extensive bone modification. To investigate this difference associated with the age of predators and bone modification, two modern Tyto alba roost samples and three modern Tyto alba nest samples were analysed to provide evidence of bone modification from adult and baby owls. Significant differences were found between these two groups, with higher rates of bone digestion associated with the nest samples, To test whether these taphonomic patterns could be identified in archaeological deposits, small mammal assemblages from four archaeological sites (The Old Vicarage at Tadcaster, Filey Roman Signal Station, Fox Hole Cave and Carsington Pasture Cave) were analysed. At one of these sites, bone digestion matched that of the Tyto alba nest sites. Bone digestion at the other three sites was higher than that recorded in this study for either Tyto alba adults or their young. This study has shown that it is possible to recognise owl nests in the archaeological record, and concludes that analysis of these assemblages can elucidate not only the origin of specific predator deposits, but can also be used to investigate the nature of human occupation, usage and abandonment of these sites