Estimating Pesticide Effects on Fecundity Rates of Wild Birds Using Current Laboratory Reproduction Tests

ABSTRACT

Regulatory agencies have used laboratory toxicity tests for decades to assess potential risks of pesticide use to wildlife, but questions remain about the ecological significance of test results. Population models may provide a valuable tool for projecting the consequences of pesticide use if information exists on the relationship between exposure and effects on survival and fecundity rates. We review issues of using avian reproduction test results for estimating changes in fecundity rates of wild birds. The avian reproduction test originated from studies focused on eggshell quality and embryotoxic effects of bioaccumulating, organochlorine pesticides. Current pesticides exhibit other potential reproductive effects that are not measured or that are poorly characterized. Because several experimental design features of the laboratory test may lead to overestimation or underestimation of the magnitude of risk of a particular pesticide to wild birds, determination of the magnitude of effects on fecundity cannot be based solely on the results of standardized laboratory tests. Quantifying the overall impact of pesticides on avian fecundity rates for use in population modeling will require additional information from modified laboratory tests that address specific questions, field monitoring or experimental field studies, and simulation models of avian productivity.

Keywords:

• avian reproduction
• population model
• fecundity
• lab-to-field extrapolation
• pesticides

ACKNOWLEDGMENTS

We thank Pierre Mineau for valuable discussions on this topic and Anne Fairbrother and John Nichols for helpful input on an earlier draft of this article. The information in this document has been funded by the U.S. Environmental Protection Agency. It has been subjected to review by the National Health and Environmental Effects Research Laboratory and approved for publication. Approval does not signify that the contents reflect the views of the Agency. This is NHEERL product number MED-04-4311.