Species- and age-related variation in metal exposure and accumulation of two passerine bird species

► We measured metal concentrations in feces and livers of two passerine species. ► We examined species- and age-related differences in polluted environments. ► Feces was evaluated as a useful non-destructive measure of increased stress. ► Generally pied flycatchers accumulated higher concentrations than great tits. ► Cadmium and selenium accumulated with age in both species.