Northern Prairie Wildlife Research Center
U.S. Fish and Wildlife Service, Northern Prairie Wildlife Research Center, Rural Route 1, Box 96C, Jamestown, ND 58401-9736
The U.S. Fish and Wildlife Service and the Canadian Wildlife Service have conducted annual surveys to estimate the number of ducks and number of wetlands containing water in major North American breeding areas since 1955. The data consist of ocular counts of ducks and ponds from low-altitude aircraft adjusted for visibility bias using data from ground surveys on a subsample of the transects. There have been major technological advances in the tools available for habitat surveys since the inception of the current surveys. To be useful and maintain the continuity of the data base, new tools must allow accurate detection of water, accurate location of transect boundaries, and rapid analysis of the data as the time for the development and review of annual hunting regulations following the survey is short. We collected large scale near infrared video in conjunction with a GPS for eight air-ground transect segments in southern Saskatchewan. Under the control of a personal computer, a sample of video frames providing complete coverage of a transect segment was transferred from tape to a video disk player. The software allows the display of the video data, the alignment and adjustment of transect boundaries, and thresholding of the video data to assist the manual interpretation. The accuracy of the manual interpretation of the video data was evaluated by comparison with ground survey data. The mean video omission error for the 8 air-ground transects was 20% (SE 3.7817, range 8-34%). The mean video commission error was 21% (SE 5.1493, range 7-50%). The time required for processing and analysis of the data is discussed. In addition to a count of ponds, video data can be used to estimate the area of water, and provides an image of current wetland and upland conditions.