Data from: Mercury exposure in an endangered seabird: long-term changes and relationships with trophic ecology and breeding success

Mercury (Hg) is an environmental contaminant which, at high
concentrations, can negatively influence avian physiology and demography.
Albatrosses (Diomedeidae) have higher Hg burdens than all other avian
families. Here, we measure total Hg (THg) concentrations of body feathers
from adult grey-headed albatrosses (Thalassarche chrysostoma) at South
Georgia. Specifically, we: (i) analyse temporal trends at South Georgia
(1989–2013) and make comparisons with other breeding populations; (ii)
identify factors driving variation in THg concentrations; and, (iii)
examine relationships with breeding success. Mean ± SD feather THg
concentrations were 13.0 ± 8.0 µg g-1 dw, which represents a threefold
increase over the past 25 years at South Georgia and is the highest
recorded in the Thalassarche genus. Foraging habitat, inferred from stable
isotope ratios of carbon (δ13C), significantly influenced THg
concentrations – feathers moulted in Antarctic waters had far lower THg
concentrations than those moulted in subantarctic or subtropical waters.
THg concentrations also increased with trophic level (δ15N), reflecting
the biomagnification process. There was limited support for the influence
of sex, age and previous breeding outcome on feather THg concentrations.
However, in males, Hg exposure was correlated with breeding outcome –
failed birds had significantly higher feather THg concentrations than
successful birds. These results provide key insights into the drivers and
consequences of Hg exposure in this globally important albatross
population.