Feathers collected from 7 raptor species in Québec between 1906 and 2002 were screened for mercury. The concentrations found in golden eagle and northern goshawk feathers decreased over time. In addition, over the 6- to 8-year period between 1989-1991 and 1997, a 33% decrease in mercury levels was observed in feathers collected from osprey chicks reared in nests close to hydroelectric reservoirs. This decrease is likely linked to a reduction in the mercury levels in the tissues of fish within the reservoirs. In general, however, feathers from bald eagles and ospreys, which feed in aquatic environments, showed mercury levels from 2 to 30 times higher than those from species foraging in terrestrial environments. In the case of the bald eagle, mercury levels were high and the concentration increased with the age of the birds.