Correlations between melanin pigmentation and element concentration in feathers of White-tailed Eagles (Haliaeetus albicilla)

The element concentration of moult feathers of White-tailed Eagles was inve stigated. Using the 2- MeV Hamburg proton microprobe we tried to differenti ate between elements incorporated into the feather via the food chain and t hose which are deposited externally onto the feather vane. Regarding incorp orated elements, special attention has been given to a possible correlation between element concentration and feather pigmentation. Concerning the ele ments detected in this work (S, K, Ca, Ti, Mn, Fe, Cu, Zn, Hg, Pb), calcium , manganese and zinc show a considerable enhancement within the pigmented f eather as compared with pigment-free feather sections. On the other hand, n o differences were found in concentrations for sulfur, titanium, iron, copp er, mercury and lead. Our findings therefore imply a special enrichment of Ca, Mn and Zn within melanin, the source of the feather's pigmentation. The possible role of these elements with regard to melanin formation is discus sed.