Approximately three–quarters of migrating autumn (fall) chinook salmon Oncorhynchus tshawytscha smolts avoided a covered channel and selected an uncovered channel when presented with a choice in an experimental flume.  Rejection of overhead cover occurred prior to, but was rare post–channel entrance.  Smolts may selectively reject riparian cover as an adaptive behavioral response to minimize predation risk and enhance rates of migration.  The findings have implications for fish bypass design and riparian habitat and culvert restoration.