Point Bennett, on western San Miguel Island, California, was an important location for sea mammal hunting through time. We use stable oxygen isotopic (δ18O) measurements from California mussel (Mytilus californianus) shells to reconstruct a seasonal pattern of mussel harvesting by the human occupants of Point Bennett during three time intervals dated to the middle (~7,550 – 3,600 cal B.P.; CA-SMI-528, Stratum 3) and late (after ~3,600 cal B.P.; CA‑SMI-528, Stratum 1; CASMI-602) Holocene. During both periods of occupation at CA-SMI-528, mussel harvesting was primarily during the spring, coincident with onshore sea mammal breeding. This suggests a seasonal pattern of site occupation. At CA-SMI-602, mussel harvesting primarily occurred during the summer and fall. This is opposite when sea mammals are present in highest densities, suggesting year-round occupation. This shows how seasonality of mussel harvesting can be used alongside other indicators like seasonal availability of sea mammals to understand broader patterns of human mobility.

Using targeted survey, excavation, and radiocarbon dating, we assess the extent to which human settlement patterns on California’s northern Channel Islands fit predictions arising from the ideal free distribution (IFD): (1) people first established and expanded permanent settlements in the regions ranked high for environmental resource suitability; (2) as population grew, they settled in progressively lower ranked habitats; and (3) changes in the archaeological record associated with high population levels such as increases in faunal diversity and evenness in high-ranked habitats are coinci- dent with the expansion to other areas. On Santa Rosa Island, the early permanent settlements were located in both high- and middle-ranked locations, with the most extensive settlement at the highest ranked locations and only isolated sites elsewhere. Settlement at a low-ranked habitat was confined to the late Holocene (after 3600 cal BP). Drought influenced the relative rank of different locations, which is an example of climate adding a temporal dimension to the model that episodically stimulated popu- lation movement and habitat abandonment. Because the IFD includes a wide range of cultural and environmental variables, it has the potential to be a central model for guiding archaeological analysis and targeted field research.

The prehistoric establishment and expansion of permanent settlements on the Northern Channel Islands of southern California generally follows a pattern predicted by the population ecology model, the ideal free distribution (IFD). We determine this by comparing the abundant archaeological record of these Islands against a careful quantification of habitat suitability using areal photography, satellite imagery, and field studies. We assess watershed area, length of rocky intertidal zone, length of sandy beach for plank canoe pull-outs and area of off-shore kelp beds, for 46 coastal locations. A simple descriptive anal- ysis supports key IFD predictions. A Bayesian model fitted with the Gibbs sampler allows us to recon- struct the Native assessment of habitat that appears to underlie this process. Use of the Gibbs sampler mitigates the impact of missing data, censored variables, and uncertainty in radiocarbon dates; it allows us to predict where new settlements may yet be discovered. Theoretically, our results support a behav- ioral ecology interpretation of settlement history, human population expansion, and economic intensifi- cation in this region. They also demonstrate Bayesian analytical methods capable of making full use of the information available in archaeological datasets.

Islands in Oceania were some of the last habitable land masses on earth to be colonized by humans. Current archaeological evidence suggests that these islands were colonized episodically rather than continuously, and that bursts of migration were followed by longer periods of sedentism and population growth. The decision to colonize isolated, unoccupied islands and archipelagos was complex and dependent on a variety of social, technological and environmental variables. In this chapter we develop an integrative, multivariate approach to island colonization in Oceania based on a model from behavioral ecology known as the Ideal Free Distribution. This ecological model provides a framework that considers the dynamic character of island suitability along with density-dependent and density-independent variables influencing migratory behavior. Unique among existing models, it can account for the episodic nature of certain aspects of the colonization process. Within this context we critically evaluate the role of foraging, lowlevel food production, and ultimately intensive food production, as important contextual variables that influenced decisions to disperse. We argue that intensive food production was one variable that contributed to decreasing suitability of island habitats, stimulating dispersal, and ultimately migrations to more distant islands in Oceania. © 2006 by The Regents of the University of California.