Wood Stork use of and contaminant levels in urban man-made water bodies in northeast Florida

Abstract

The federally listed Wood Stork (Mycteria americana) is dependent on shallow, ephemeral wetlands for foraging. Most of these natural wetlands have been lost in Florida due to increased urban development, but numbers of man-made bodies of water have increased. I used program PRESENCE to predict stork occurrence in man-made water bodies. Storks were more likely to be detected relatively far from the nesting colony, suggesting that late in the breeding season, storks use water bodies relatively far from their nesting colony to find available and abundant prey. Additionally, storks were more likely to be detected when other wading birds were present, reflecting their social and opportunistic foraging behavior. During the summers of 2007 and 2008 I collected samples of prey items and sediment from 30 sample sites, and dead or moribund chicks from the Jacksonville Zoo stork colony for analysis of 18 inorganic elements, 46 polycyclic aromatic hydrocarbons (PAH), and a suite of eight organophosphate and 29 organochlorine pesticides. I did not detect organophosphates in samples of sediment, prey, or chicks. When detected, concentrations of metals, PAHs, polychlorinated biphenyls (PCBs), and organochlorine pesticides in sediment, prey, and chicks were below previously reported effects thresholds for birds. Each water body type harbored a fairly unique contaminant profile. I concluded that overall risk to storks from foraging in man-made water bodies in the Jacksonville, FL area was likely low but requires further investigation, particularly for selenium and PAHs.