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.