Northern Prairie Wildlife Research Center
Monitoring the status of swift fox populations was one of the goals identified in the swift fox conservation plan. We propose that monitoring swift presence, if done properly, should suffice to detect declines in number and/or distribution. Although presence has been commonly used as a measure of a species persistence over time, the variable nature of sampling efforts restricts the usefulness of these records. Probability of detecting the presence of a species, even if present, is rarely known and if the area sampled is large enough to include numerous individuals, a decline in numbers may not be detected until the last animal dies.
We estimated the probability of detecting swift foxes using remote cameras at tracking plates set within home ranges of radio-collared swift foxes in southeastern Wyoming. Short transects (1 km) reduced the number of foxes exposed to each transect. Detection rates of foxes in June was 67%. Transects were run again in August. We then used these estimates of detection to calculate the number of transects needed to detect differing levels of decline in swift fox presence. Characteristics of survey design (transect length, number of tracking plates and timing) are discussed.