As with other periods of prehistoric isotopic research, some research in Scotland has been undertaken, but has largely focused on the islands and other areas of good bone preservation. Little research has been conducted in Perth and Kinross to date. For example, a study of human burials and contemporary animal remains from East Lothian, including sites of Port Seton, Broxmouth, Winton House and Dryburn Bridge, concluded that terrestrial sources of protein such as cattle, sheep and to a lesser extent pigs were the dominant contributors to diet in the period (Dunwell 2007; Jay and Richards 2007). The data also suggest that, like Iron Age isotope and zooarchaeological data from other parts of Britain, marine fish was not widely consumed even at coastal sites. Thus, such studies have great potential to not only reveal dietary habits but also wider economic practice and even cultural preferences. Indeed, the lack of marine fish bones in British Iron Age contexts, and by extension the lack of marine fish in human diet inferred by stable isotopes in the same period, has led some to conclude that the consumption of marine fish may have been somehow prohibited, taboo or that other cultural aversions may have existed (Dobney and Ervynck 2007).
Beyond diet, and where multi-isotope methods are employed, the movement histories of individuals or groups have also been invested in Scotland in this period using isotope techniques. This period is of particular interest given the potential interactions between local populations and the Romans in the south of Scotland, and any differences in diet or movement histories that may have occurred either due to a direct or indirect ‘Romanising’ influence or due to a direct impact by Roman military activity. For example, the recent analysis of a group of Iron Age and Roman burials from Musselburgh in East Lothian revealed that Iron Age diet in this part of Scotland was low in marine fish but enrichment in 15N led the authors to conclude that freshwater fish may have been consumed. The data from this study also indicated a high degree of individual mobility in the Roman burials compared to the earlier Iron Age individuals, and particularly of individuals who had been decapitated. While the decapitated individuals did not have a commonplace of origin, their non-local isotopic signatures highlighted that these individuals were not a continuation of a native Iron Age population. Instead they were likely to have been members of the Roman army themselves; this highlights the shared burial practice amongst the ethnically diverse Roman army (Moore et al 2020). Despite the success of analyses elsewhere in Scotland, there has been a lack of stable isotope studies conducted on Iron Age material in Perth and Kinross. As with other periods prior to the early medieval, this is a consequence of a lack of bone preservation and/or a dearth of radiometric dating of unassigned burials.
In Perth and Kinross specifically, there are examples of Iron Age human isotope data published to date, although no specific isotope research projects have been undertaken. These have instead, for the most part, been data produced through the course of radiocarbon dating. For example, from The Women’s Knowe, Inchtuthil, stable carbon and nitrogen isotope data from bone collagen of one individual were produced alongside a radiocarbon date. The d13C and d15N data were -21.6‰ and 10.5‰ respectively (Winlow and Cook 2010, 55), indicating that dietary protein was terrestrial in origin (ie meat or dairy).
The cataloguing of collections of Iron Age human and animal material exist within Perth and Kinross or may be held in other national institutions, and originate from the region.
The radiocarbon dating of isolated unclassified prehistoric human burials in order to identify further material. This should be conducted as part of commercial work, local museum or heritage initiatives, or research projects. The dating of existing museum collections, as well as new finds, should be considered a priority.
Given that stable carbon, nitrogen and sulphur isotope data can be generated alongside radiocarbon dates in some institutions (e
.g ., at SUERC), such an approach should be undertaken to maximise initial destructive sampling of any skeletons.
As with other periods, the analysis of childhood diet and of early-forming tissues to infer breastfeeding and weaning practices could also be illuminating in the Iron Age as very little is known about these practices in prehistory.