Concentrations of metals in liver, muscle and feathers of tree sparrow: age, inter-clutch variability, gender, and species differences.

Metal (arsenic, mercury, cadmium, lead, nickel, cobalt and manganese) concentrations were analyzed in muscles, livers and ventral plumage of Tree Sparrows (Passer montanus). Differences in metal concentrations between adults and chicks, inter-clutch and species were studied. The levels of metals accumulated with age, and the adults have higher concentrations of metals. Female had lower mercury level than that in male, which means female can excrete mercury by egg-laying. The eggs laid in the first brood had relatively higher concentrations of metals than those in the second ones. For different species, the location they habitat is more important when they share a similar diet and circumstance.