Using Feathers to Determine Mercury Contamination in Peregrine Falcons and Their Prey

Abstract

Abstract We document concentrations of total mercury (Hg) in feathers of Peregrine Falcons (Falco peregrinus) from 12 territories in Lake Mead National Recreation Area (LMNRA) and five territories in an adjacent southern Nevada (SNV) study area during 2012 and 2013. We also report total Hg concentrations in feathers of 94 species (337 individuals) collected as prey remains from peregrine nesting areas from 2008–2013. All peregrine feathers contained total Hg (range = 0.12–42.54 µg/g), and adults had a significantly higher mean total Hg concentration (12.19 µg/g) than hatch-year peregrines (3.76 µg/g). Mean total Hg concentrations in peregrines in LMNRA (adult = 17.24 µg/g, brood = 5.82 µg/g) were significantly greater than in SNV (adult = 2.7 µg/g, brood = 0.67 µg/g) for both age classes. Among peregrine territories, mean total Hg in prey was positively correlated with the proportion of aquatic birds taken as prey (biomass), and negatively correlated with distance of eyries to water. Among avian...