We assessed total mercury concentrations in breast feathers of diurnal North American raptors collected at migration monitoring stations. We sampled raptor feathers from 9 species in the Pacific Flyway and compared species, sex, date, and flyway effects on mercury concentrations. We also explored year effects on 3 species of raptors in the Pacific Flyway during 13-years (2002-2014). Finally, we compared mercury concentrations in merlin among 4 continental flyways.