The authors investigated the effects of hydroelectric development on the movements and space-use of caribou (Rangifer tarandus) in west-central Newfoundland, Canada. The authors compared patterns of range use, site fidelity, and timing of migration before, during, and after project construction. Coincidental with the first year of project construction, caribou were less likely to be found within 3 km of the site; this persisted at least 2 years after construction was completed.