The Feasibility of Nightlighting for Monitoring Brood Production of Wood Ducks on Rivers

To determine the applicability of the nightlighting technique for monitoring wood duck (Aix- sponsa) brood production on rivers in Tennessee, we compared results of day and night surveys on 8 rivers in spring 1990. Results of 32 day counts and 16 night counts showed that 112% more broods/km were seen at night (X = 0.55, SE = 0.022) than day (X = 0.26, SE = 0.20). The mean number of broods/km did not differ (P < 0.05) between replications for either night counts or day counts. There was a significant (P = 0.01) but weak (R = 0.61) relationship between the first day counts and night counts and no relationship (P = 0.50, R = 0.19) between the second day counts and night counts. We surveyed Tennessee Wildlife Resources Agency (TWRA) personnel (N = 23) who participated in night and day surveys to determine their opinions of both techniques. As a control, questionnaires also were given to 20 other TWRA personnel who had conducted only daytime surveys. All respondents felt safe conducting daytime surveys. Night workers (39%) felt that day surveys were safer than night surveys, but 61% felt there was little difference in safety between techniques. Day workers (68%) responded that day surveys were safer and 32% said there was little difference in safety between day and night surveys. Ninety-six percent of night workers and 90% of day workers said they would not reject either day or night technique due to safety concerns, and 100% of both groups said they would be willing to take part in the survey technique which proved to be most useful in monitoring wood duck trends. We believe that the nightlighting technique is a more efficient and effective management tool for monitoring wood ducks on appropriate rivers and that the technique would be readily accepted by wildlife professionals.

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