trace element residues in eggshells of grey heron (ardea cinerea) and black-crowned night heron (nycticorax nycticorax) from nallihan bird paradise, ankara-turkey. | concentrations of four trace elements (cd, ni, cu and pb) were determined in eggshells of grey heron (ardea cinerea) and black-crowned night herons (nycticorax nycticorax) from nallihan bird paradise, which is located in the northern part of sariyar dam reservoir, turkey. results indicated that, within the same area, these ardeid species differed in the levels of cd, cu and pb in their eggshells (generally grey heron > night heron), possibly because females may have foraged in different habitats ... | 2007 | 17364239 |