Influence of car traffic on lead contamination in tissues of juvenile Parus major during postnatal development

Abstract

The main objective of our research was to identify the impact of external factors (spatial and time) on the amount of lead in the tissue great tit nestlings (Parus major) during ontogenesis in the submontane region of the High Tatra mountains. The research was carried out in the vicinity of several roads in the municipalities of Štrbské Pleso, Tatranská Lomnica, and Starý Smokovec in 1995-1996. The results confirmed that the amount of Pb found in tissues of great tit nestlings were different between studied sites, likely due to variation in traffic density. The size of each clutch also affects the amount of Pb in tissues. Lead content in tissues of nestlings from nests with a larger number of siblings (a larger clutch), is lower than in the tissues of individuals from a smaller clutch. The amount of lead rises with age; however, it does not depend on individual size predisposition. An insignificant increase in Pb levels were recorded during periods of bone growth (ulna/radius and tarsometatarsus). The amount of lead increased with increasing weight and with growing feathers. This means that Pb is taken up through the process of ontogenesis, mainly via feeding and it quickly accumulates into soft tissues and rapidly growing feathers. The lead level increased with rising weight and growing feathers, which points to accumulated lead derived mostly through feeding. The nestlings at sites with lower intensity traffic exhibited accelerated growth of feathers, as more metabolism was invested in plumage growth. This is considered a positive trend, as plumage growth correlates to an earlier departure from the nest.