Productivity and density of belted kingfishers on the Housatonic river, Massachusetts
Belted kingfishers (Ceryle alcyon) breeding along the Housatonic River (Massachusetts) were studied to determine whether productivity or population density is impaired, in light of the presence of polychlorinated biphenyls (PCBs) in their prey. The study involved: a) characterizing habitat quality; b) identifying kingfisher burrows; c) monitoring breeding pairs from courtship through fledging; d) collecting nest remnants to characterize predominant prey; e) estimating PCB doses; f) testing whether the estimated dose of PCBs, habitat suitability, hatch date and/or nest density were significant predictors of survival to 26 days and g) comparing observations to the scientific literature. In 2002, ten kingfisher burrows were identified along the Housatonic River, of which one was destroyed by human excavation and three were depredated. The study area is supporting a kingfisher population consistent with the quality of available habitat. That population is breeding successfully, with productivity and population density consistent with values reported in the scientific literature. There were no significant relationships between estimated doses of PCBs and reproduction. However, consistent with expectations, the proportion of nestlings surviving to 26 days was significantly greater with earlier fledge dates.