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FIELD DEPLOYABLE TECHNIQUES TO MONITOR EXPOSURE TO ENVIRONMENTAL ESTROGENS THROUGHOUT THE REPRODUCTIVE CYCLE OF WILD BIRDS
Citation:
McQuillen, H., L. Brewer, A Fairbrother, J. Clark, AND R S. Bennett. FIELD DEPLOYABLE TECHNIQUES TO MONITOR EXPOSURE TO ENVIRONMENTAL ESTROGENS THROUGHOUT THE REPRODUCTIVE CYCLE OF WILD BIRDS. Presented at 21st SETAC Annual Meeting, Nashville, TN, November 12-16, 2000.
Description:
Concern about potential for endocrine disrupting chemicals to interfere with normal breeding behaviors of wildlife prompted this study of effects of exposure to environmental estrogens during the breeding cycle of wild birds. The house finch (Carpodacus mexicanus) was selected as a model as it is ubiquitous in the US, sexually dipmorphic, an obligate seed eater, and can lay up to five clutches of eggs in a breeding season. Two field-deployable monitoring techniques were developed. The first technique used miniature video cameras to remotely monitor reproductive behaviors and success of nesting birds. The second used a competitive binding enzyme immunoassay to measure the amount of estrone conjugate excreted in fecal-urates. Reproductive behaviors of wild, captive house finches recorded using videography included courtship, nest building, egg laying, incubation, and brood rearing. Results demonstrated that reproductive behaviors and nesting success could be quantified within five-minute resolution using this technology. Analysis of fecal-urate samples, collected on four-day intervals, demonstrated the feasibility of quantifying and monitoring changes in excreted estrone conjugate as correlates of reproductive behavior. Using Spearman's Rank Correlation, nest building behavior correlated significantly (P < 0.005, n = 28) with fecal estrone conjugate levels. Nest material handling, food begging, and incubation behavior were not significantly correlated to the amount of excreted estrone conjugate. These results suggest that remote videography together with measures of estrone conjugate excretion may provide a method for monitoring free-ranging wild birds to determine if their endocrine systems are being modulated at ecologically relevant levels by exposure to environmental estrogens.