Two populations of the European bee-eater were studied, one living at a reference site and the other at a metal mining site. The concentration of arsenic and 11 metals (Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn) was measured in feathers and regurgitated pellets collected at both sites. Cadmium, chromium, mercury, nickel, and lead were at least twofold higher in feathers of birds from the contaminated site than in the reference site, suggesting that this population was exposed to higher metal levels. Similarly, levels of aluminum, arsenic, cadmium, cobalt, chromium, iron, and lead were also at least twofold higher in pellets from the contaminated area. The obtained results suggested that the impacted population of Merops apiaster is at risk due to the exposure to some metals.

The seasonal diet and size of fish prey of the otter Lutra lutra were studied in an almost pristine river of North Portugal (Paiva river) through the analysis of spraints collected during 1 year. To identify Iberian freshwater fish species (Salmo trutta, Micropterus salmoides, Lepomis gibbosus, Luciobarbus bocagei, Cyprinus carpio, Carassius auratus, Pseudochondrostoma polylepis, Achondrostoma arcasii, and Iberocypris alburnoides) consumed by the otter keys based on scales and vertebrae were first developed and tested. Both keys allowed identification of all fish species, although three Cyprinidae species could not be discriminated (P. polylepis, A. arcasii, and I. alburnoides). Regression equations were calculated to estimate the dimensions of preyed fish. Highly significant linear relationships were obtained for the standard length versus vertebrae measurements, for all fish species, except for C. carpio. Fish was the predominant prey category in autumn and winter, but the otter also preyed on amphibians, reptiles, mammals, and birds, particularly during spring and summer. In general, the otter consumed high proportions of small size fish (3–12 cm for the three indiscriminate Cyprinidae, 3–9 cm for C. carpio, and 6–12 cm for S. trutta).