Limited effects of heavy metal pollution on foraging and breeding success in the curlew (Numenius arquata)

We examined the effect of heavy metal pollution on the foraging success and breeding performance of the curlew (Numenius arquata) along a documented pollution gradient from a point source, and also by comparing foraging and breeding parameters between the polluted site and two non-polluted areas. Prey biomass and abundance, and foraging success did not vary along the pollution gradient, and were no less at the polluted site than in the non-polluted areas. Furthermore, there was no difference in adult weight during incubation between the polluted and non-polluted areas. There were also no differences in measures of breeding success along the pollution gradient, or between areas, which could be attributed to pollution per se. Egg shells from the polluted area had higher concentrations of heavy metals than in the non-polluted areas, and egg shells close to the pollution source were contaminated more than those further from it. However, there was no difference in calcium concentrations of egg shells or egg-shell thickness between areas. We conclude that in this study there were minimal immediate effects of heavy metal pollution on foraging and breeding success in the curlew.