Surveys had to be simple and easily integrated with other study objectives, namely obtaining data on nest success in ducks. Therefore, we devised a variety of survey methods that could be systematically applied during the duck nesting season, allowing us to capitalize on observations by the numerous individuals already working in each study area.
Spring is a good time to survey predator populations because most predators are caring for young.
Predators were surveyed by persons or crews whose primary duty was to gather data on nest success in ducks, by other biologists working in the study areas, and by specialists in surveys of predators who moved among study areas. Each crew was responsible for gathering data in two or three study areas in a given year. Individuals responsible for conducting surveys and for maintaining records were instructed in survey methods and given written survey guidelines. All data from surveys of predators except sightings were recorded by quarter section or combinations of quarter sections.