DISPERSAL

Every species has a dispersal phase in its life cycle, wherein the young tend to leave their birth range and establish a new adult home range. Among whitetails, yearling bucks are more likely to disperse, and travel greater distances, as compared to young females.

More importantly, for intensively managed whitetail populations, understanding dispersal traits is critical if managers expect to manipulate deer population densities, sex ratios and age structures, and curb the spread of diseases such as bovine tuberculosis and chronic wasting disease.

As explained by researcher Jonathan Shaw and his colleagues from North Carolina State University, emigration (outward movement) and immigration (inward movement) are difficult to measure and are typically assumed constant and equal in population analysis. However, when emigration and immigration are dynamic and not equal, decreased accuracy in projected population density, sex ratio and age structure estimates occur.

For example, if more young bucks leave a given population than enter, or if those entering suffer greater mortality, a net loss of yearling bucks may result.

As pointed out by Larry Marchinton and Karl Miller, dispersal might increase the proportion of females to adult males if the departure of males is not canceled out by an influx of males from adjacent range, because females are so sedentary.

Hence, not only is it important for managers to know how many young bucks leave and enter a given population, they must