stylistic:tone, information:filtering
Migration from the homeland

Current scholarly consensus is that Ancestral Puebloans responded to pressure from Numic -speaking peoples moving onto the Colorado Plateau, as well as climate change that resulted in agricultural failures. The archaeological record indicates that for Ancestral Puebloans to adapt to climatic change by changing residences and locations was not unusual. Early Pueblo I Era sites may have housed up to 600 individuals in a few separate but closely spaced settlement clusters. However, they were generally occupied for 30 years or less. Archaeologist Timothy A. Kohler excavated large Pueblo I sites near Dolores, Colorado, and discovered that they were established during periods of above-average rainfall. This allowed crops to be grown without requiring irrigation. At the same time, nearby areas that suffered significantly drier patterns were abandoned.