SREL Reprint #2491

Integration of research with long-term monitoring: breeding wood ducks on the Savannah River Site

Robert A. Kennamer and Gary R. Hepp

Abstract: In 1981, long-term monitoring of the breeding of Wood Ducks (Aix sponsa) was initiated on the Savannah River Site by the Savannah River Ecology Laboratory in partial response to environmental legislative requirements surrounding the restart of a U.S. Department of Energy nuclear production reactor (L-Reactor). Although the reactor itself was operated only for two years, the study of Wood Ducks continues today, 15 years following its initiation, and has made significant contributions to our basic understanding of the population ecology of this unique species, and waterfowl in general.
Marking and recapturing individual females in nesting boxes were key aspects of the long-term study because it enabled us to produce annual population parameter estimates (e.g., population size, survival rate, recruitment), which are valued indicators of population stability. We were able to generate precise parameter estimates, though marking relatively small numbers of breeding females, because capture probabilities were high. Identifying field methods (e.g., long-term consistency in capture effort) that allowed precise parameter estimation was among the most important consequences of our work. The longevity of the monitoring effort was also important because it allowed us to examine the natural range of variation in reproductive characteristics of this species. We used retrospective analyses of the long-term data and initiated companion short-term studies to explore factors related to and responsible for the identified variation within the population.
Our work illustrates some of the beneficial aspects of ecological research derived from long-term monitoring efforts: they generate essential baseline data and provide a means of continually refining management practices, provide answers to important ecological questions that cannot be addressed easily by using experimental methods, and establish a foundation for formulating and testing new hypotheses. In this paper, we review the conditions that motivated the initiation of this study, the initial goals of the work, and the ecological knowledge that has been gained thus far from the commitment of SRS managers and researchers to long-term population monitoring.

Keywords: Aix sponsa; Anatidae; breeding ecology; long-term study; population ecology; Savannah River Site; South Carolina; Wood Duck

SREL Reprint #2491

Kennamer, R. A., and G. R. Hepp. 2000. Integration of research with long-term monitoring: breeding wood ducks on the Savannah River Site. Studies in Avian Biology 21:39-49.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).