Natal dispersal is a multi-phase process during which young animals leave their natal area (departure), explore surrounding areas (search), and finally settle (settlement). Despite the critical role of dispersal in determining the physical and social environments of individual animals, and the influence of dispersal on population and metapopulation dynamics, studies examining the complete dispersal process in nature remain extraordinarily rare. In this dissertation, I used both livetrapping and radiotelemetry techniques to investigate the dispersal and habitat selection behavior of brush mice (Peromyscus boylii) in a heterogeneous landscape.

Because the dispersal and habitat selection decisions of individuals may be influenced by population density and adult fitness in different habitat types, I conducted a 2.5-year catch-mark-recapture study to document the population ecology of brush mice in two distinct habitat types, woodland and chaparral (Chapter 1). I found that population density, population growth rate, and several components of fitness (survival, adult mass, reproductive activity and reproductive success) were comparable for brush mice living in the two habitats.

In Chapter 2, I described the movement patterns of dispersing juveniles during the search phase of dispersal, and investigated the decision rules that dispersers might use to select a place to settle. I found a high degree of individual variation in movement behavior during search. In particular, some individuals were extremely sedentary and did not venture beyond the area immediately surrounding their natal nest, while other individuals made repeated long-distance excursions. Overall, dispersers appeared to use comparative decision rules during search, making repeat visits to particular nest sites and geographic areas before settlement.

Finally, in Chapter 3, I investigated the role of natal habitat type on behavior during both the search and settlement phases of dispersal. Natal habitat preference induction (NHPI) may affect behavior during dispersal, by increasing the probability that dispersers will both search and settle within their natal habitat type. I found that individuals both explored and settled within their natal habitat type more frequently than expected based on natal habitat type availability. This study presents the first documentation of NHPI when individuals naturally disperse through a landscape composed of multiple unique habitat types.