Banner image: Salado potters, by Robert B. Ciaccio
Our test excavations at Classic period (1200-1450) residential sites in the San Pedro River valley provided us with several interesting lines of evidence for thinking about the Salado phenomenon and population decline across the southern Southwest in the centuries before the arrival of the Spaniards.
In the San Pedro, population decline was complex and gradual. Shortly after Kayenta migrants arrived in the late 1200s, local groups aggregated into eight or ten large villages and constructed platform mounds. Not long before, they had been living in a greater number of smaller, dispersed settlements. This coming together probably occurred partly in response to Kayenta immigration. Migrants themselves lived apart from the local populations, at first.
Over time, and after a century of gradual population loss, social boundaries between these two groups were bridged. Population losses may have been due to poor health conditions and localized environmental degradation around these very large villages. Communities had to find ways to maintain irrigation systems and exchange networks, among other needs. Local and migrant descendants forged a new cultural and religious identity—Salado. This new identity helped to bring them together as one people and fostered cooperation during a time of crisis. Even so, by 1450, most people had left the San Pedro valley.
We decided to examine the relationships among migration, aggregation, and population decline across the southern Southwest, beyond the San Pedro valley. This research was funded by the National Science Foundation (BCS-0342661). One of our most important tools was a GIS (Geographic Information Systems) database that came to be known as the Coalescent Communities Database (now the Heritage Southwest Database). It contains information about the sizes and dates of Southwestern archaeological sites with more than twelve rooms that date between 1200 and 1600. During this time, many groups were living in above-ground masonry structures, making it easier to count rooms and estimate population. We also examined existing artifact collections from sites in the Phoenix, Tonto, and Safford basins of southern Arizona, and from Perry Mesa, an area north of Phoenix.
We identified at least one major migration of northern people in the late 1200s, primarily Kayenta groups who moved into east-central and southeastern Arizona. Other northern groups also migrated southward, although many of these movements remain poorly defined. The San Pedro pattern of migration and local aggregation, followed by decline and dispersal, is apparent in nearly every study area. To go in-depth with our findings, visit our online exhibit, Pieces of the Puzzle: New Perspectives on the Hohokam.
We also suspected that when groups began leaving large communities in the San Pedro valley and other parts of southeastern Arizona in the late 1300s, some headed into the upper Gila River valley and nearby areas of southwestern New Mexico. Click here to continue reading about the next phase of our research.