Mercury concentrations in primary feathers reflect pollutant exposure in discrete non-breeding grounds used by Short-tailed Shearwaters

We measured mercury concentrations ([Hg]) and nitrogen stable isotope ratios (δ15N) in the primary feathers of Short-tailed Shearwaters (Puffinus tenuirostris) that were tracked year-round. The [Hg] were highest in 14 birds that used the Okhotsk and northern Japan Seas during the non-breeding period (2.5 ± 1.4 μg/g), lowest in nine birds that used the eastern Bering Sea (0.8 ± 0.2 μg/g), and intermediate in five birds that used both regions (1.0 ± 0.5 μg/g), with no effects of δ15N. The results illustrate that samples from seabirds can provide a useful means of monitoring pollution at a large spatial scale.