Activity, a Neglected Parameter in Population Estimates--The Development of a New Technique

Publisher Website
Google Scholar
Abstract
A combination of trapping and tracking was used to estimate population levels of the masked shrew (Sorex cinereus) over a 3-year period. This new technique is based on the principle of measuring the relative decrease in activity in an area due to the removal of a known number of animals. The population estimate is determined by calculating the number of shrews that would have to be removed to reduce activity to zero. The system eliminates two large families of errors that have plagued systems of population estimates. It eliminates all variables relating to changes in rates of animal activity due to climate, season, availability of food, natality, mortality, or others. It also resolves the age-old problem of calculating effective size of the trap plot. The method has built into it procedures and tests that assure adequate sample sizes.