Metal Contaminant Exposure In Nestling Black-Crowned Night-Herons (Nycticorax Nycticorax) In Baltimore Harbor (poster)

GOLDEN, N.H., M.A. Ottinger, P.C. McGowan, K.C. Parsons, S.C. Schmidt, and J.E. Iocubucci

In 1998, an initial assessment of the possible contribution of metal pollution to declining heron populations in Chesapeake and Delaware Bays was conducted. Study sites included two heronries in industrialized locations (Baltimore Harbor, MD and Pea Patch Island, DE), and a remote reference site (Holland Island) in southern Chesapeake Bay. Concentrations of 19 metals, metalloids, and trace elements were examined in blood and breast feathers of 14-16 day old nestling black-crowned night-herons. Metal concentrations in blood were low and showed few site differences, though mercury was elevated at Patch Pea Island as compared to Baltimore Harbor and the reference site. In feathers, metal concentrations appeared to be in the low to moderate range at all sites, though limited data exist for interpreting pollutant concentrations in feathers of nestling wading birds. Where differences were detected, concentrations at Pea Patch Island were consistently greater than those at Baltimore Harbor and Holland Island, specifically for aluminum, barium, iron, lead, magnesium, and manganese. Feathers collected in Baltimore Harbor had significantly greater concentrations of lead than the reference site, though levels of all other elements were remarkably low, with values statistically equivalent to or lower than those of the reference site. In 1999, controlled exposure studies were performed to aid in the interpretation of lead concentrations in feathers for this species and to assess the effect of various doses of lead on growth and survival of nestlings. Analysis of these data are in progress.