Metal levels in the bones and livers of globally threatened marbled teal and white-headed duck from El Hondo, Spain

El Hondo is a key area for marbled teal and white-headed duck. We present Pb, Cu, Zn, Se, and As data for bone and liver in birds found dead between 1996 and 2001. Several metals were higher in adult white-headed ducks than in marbled teal. They were higher in female than in male white-headed ducks, and did not differ with sex in marbled teal, but did by age. Lead in liver of adults was influenced by Pb shot ingestion, which was detected in 21% of marbled teal and in 71% of white-headed duck. No marbled teal had liver levels indicative of Pb poisoning, while 86% of white-headed ducks did. Selenium, Zn, and Cu were elevated in 13%, 7%, and 39% of birds, respectively. Whilst Pb shot poses the greatest threat to these species, further work should assess exposure via plants, invertebrates, water, and sediments for other metals, and investigate possible sub-lethal effects.