Biases in Aerial Transect Surveys for Moose during May and June
Gasaway WC, Dubois SD, Harbo SJ. 1985. Biases in Aerial Transect Surveys for Moose during May and June. The Journal of Wildlife Management. 49(3):777-784
Biases were identified that affect estimates of moose (Alces alces) population size, trend, composition, and behavior during aerial transect surveys in May and June. Sightability of moose was 36% in May and 26% in June. Low and variable sightability of moose preclude making accurate population estimates and precent detection of population trends without large changes in population size. Sightability of moose varied widely with habitat type used, activity, and group size; reliable estimates of these parameters cannot be obtained from moose seen on aerial surveys during May and June. Differential behavior among sex and age-classes of moose produced biases in a predictable direction for estimates of population sex and age composition. Prior to calving, yearling : cow ratios were overestimated. During May and June, calf : cow ratios were underestimated, and during June bull : cow ratios were overestimated. Biases in aerial surveys can be reduced by substantial increases in search effort, but these would increase the cost of surveys.
- Type
- Journal Article
- Authors
- Gasaway, William; Dubois, Stephen; Harbo, Samuel
- Units
- CAKN , DENA , WRST , YUCH
- Keywords
- Abundance, Aerial Surveys, Alces alces, Distribution, Mammals, Population Trends, Ungulates