The Long-tailed Skua, a small (<300 g) Arctic-breeding predator and seabird, is a functionally very important component of the Arctic vertebrate communities in summer, but little is known about its migration and winter distribution. We used light-level geolocators to track the annual movements of eight adult birds breeding in north-east Greenland (n = 3) and Svalbard (n = 5). All birds wintered in the Southern Hemisphere (mean arrival-departure dates on wintering grounds: 24 October-21 March): five along the south-west coast of Africa (0–40°S, 0–15°E), in the productive Benguela upwelling, and three further south (30–40°S, 0–50°E), in an area extending into the south-west Indian Ocean. Different migratory routes and rates of travel were documented during post-breeding (345 km d−1 in late August-early September) and spring migrations (235 km d−1 in late April) when most birds used a more westerly flyway. Among the different staging areas, a large region off the Grand Banks of Newfoundland appears to be the most important. It was used in autumn by all but one of the tracked birds (from a few days to three weeks) and in spring by five out of eight birds (from one to more than six weeks). Two other staging sites, off the Iberian coast and near the Azores, were used by two birds in spring for five to six weeks. Over one year, individuals travelled between 43,900 and 54,200 km (36,600–45,700 when excluding staging periods) and went as far as 10,500–13,700 km (mean 12,800 km) from their breeding sites. This study has revealed important marine areas in both the south and north Atlantic Ocean. Sustainable management of these ocean basins will benefit Long-tailed Skuas as well as other trans-equatorial migrants from the Arctic.

Temporal dynamics of persistent organic pollutants (POPs) were examined in fasting common eider (Somateria mollissima) females in one subarctic (68° N; over 5 years) and one high arctic colony (78° N; 3 years). Blood concentrations of polychlorinated biphenyl (PCB)-153; 1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p'-DDE), and hexachlorobenzene (HCB) were measured twice each season in eider females (total n = 162) during incubation (at day 5 and day 20). The mean wet weight concentrations of PCB-153 were ~3-5 times higher in the subarctic colony, whereas p,p'-DDE and HCB concentrations tended to be higher in high arctic than in subarctic eiders late in the incubation period. All POPs increased during incubation fast, but the relative increase in mean concentration varied more among years in high arctic than in subarctic eiders. In the high arctic, both lipid-metabolism and the increase in circulating POP concentrations were highest in the year when the mean ambient temperature was lowest. Moreover, females with low body condition and high lipid metabolism (body mass loss) had stronger increase in circulating concentrations of p,p'-DDE and HCB; the effect size being within the same order of magnitude in the two colonies. Hence, since eiders at high latitudes metabolized relatively more lipids, they experienced higher exposure of p,p'-DDE and HCB over the incubation period than birds inhabiting the more benign subarctic region.

No abstract

The distance to sources and the long-range transport potential of persistent organic pollutants (POPs) are important in understanding the impact of anthropogenic pollution on natural seabird populations. The present study documented blood concentrations of POPs in the Baltic Sea (Tvärminne, Finland) population of common eiders (Somateria mollissima) in 2009 and in 2011 and compared the concentrations with the presumably less exposed Arctic population in Svalbard (Kongsfjorden, Norway). The Baltic population had 26, 10, and 5 times greater concentrations of hexachlorocyclohexane, polychlorinated biphenyls, and p,p'-dichlorodiphenyldichloroethylene than the Svalbard population. Unexpectedly, concentrations of chlordanes were higher in Svalbard eiders, whereas concentrations of hexachlorobenzenes (HCBs) did not differ between the 2 populations. Although the similar HCB levels may partly be explained by the high transport potential of HCBs, unknown factors may have been more important than distance to sources and long-range transport potential for the chlordanes. One plausible explanation may be that the fasting-related redistribution of POPs from fat to blood was greater throughout the incubation in Arctic eiders, causing them to have higher blood levels of these POPs at the end of incubation. The blood concentrations of POPs in Baltic eiders were higher than documented in any other eider population and were comparable to levels in seabirds feeding at higher trophic positions in the food chain. Environ Toxicol Chem 2016;35:1526-1533. © 2015 SETAC.

No abstract