We are continuing research on unmapped headwater streams in the Swift River watershed, the source of water supplying the Quabbin Reservoir in Central Massachusetts. Prior work (Brooks and Colburn 2011) documented significant lengths of headwater stream channels upstream of mapped stream origins. Current studies are comparing invertebrate abundances, community composition, functional feeding groups, and drift, as well as leaf decomposition and transport, in a subset of mapped and unmapped study streams.