Effects of environmental metal pollution on breeding populations of pied and collared flycatchers in Niepołomice Forest, Southern Poland

In 1990–93 the breeding performance of pied and collared flycatcher populations (Ficedula hypoleuca and Ficedula albicollis) was studied in Niepołomice Forest at Stanisławice (Cracow Province). Concentrations of the non-essential elements cadmium and lead in bird tissues were higher than those measured at Tavelsjö (Sweden), the reference site (Nyholm et al., 1994). The highest cadmium concentrations, up to 0.35 μg/g, were found in liver. The highest lead levels, up to 1.09 μg/g, occurred in breastbone samples. Levels of copper, zinc and iron were close to physiological norms. The main source of these elements in nestlings was likely to have been their diet. The number of fledged nestlings (3.2–5.2) in Stanisławice was lower than in Tavelsjö (6). The high percentages of nestlings with low levels of haemoglobin suggest that this may be the main factor contributing to the lower survival rates at Stanisławice.