PRELIMINARY REPORT ON ACCURACY OF AERIAL MOOSE SURVEYS

Abstract

Sample quadrats were established around radiocollared moose and each quadrate was surveyed with a search intensity of approximately 4 to 5 min/mi² using transect/contour searches similar to standard Alaska Department of Fish and Game surveys. A second, more intensive search of 10 to 13 min/m² was then made of each quadrat. Substantially more moose were seen during the intensive search than during transect/contour surveys in all three physiographic areas. Habitat selected by moose was the most critical environmental factor affecting sightability of 45 radiotagged moose. During early and late winter, 84 and 61 percent, respectively of the radiocollared moose selected habitat types with low canopies (herbaceous, low shrub, and tall shrub). Moose using these open habitats were easier to see regardless of search intensity. Moose using forest habitats were often missed during the initial transect/contour survey but were usually seen later during the intensive search. Spruce-dominated quadrats were the only areas in which uniformly high sightability could not be achieved with intensive search effort. Activity of moose also affected sightability. Lying moose were missed more frequently than standing moose during transect/contour surveys and intensive searches. Snow condition was identified as having considerable influence upon sightability, but the adverse effects of poor snow condition were largely overcome by intensive search effort. The application of these data to moose trend surveys and censuses is discussed.