Search strategies in rural and urban environment during natal dispersal of the red squirrel

摘要

Decisions made during natal dispersal highly influence the future fitness of the animal. The selection of future home range affects, for example, food supply and mating success. In order to select between potential sites, dispersing individuals may use different search strategies, and for example, aim to compare quality of different sites by revisiting them. Alternatively, dispersers visit new sites without comparison until a suitable site is located. By using radio telemetry, we studied search strategies during natal dispersal in both urban and rural environments. We examined what kind of sites juvenile red squirrels (Sciurus vulgaris) choose as their home range from all visited sites and whether they display revisit behavior during natal dispersal. We found that most of the dispersing individuals perform revisits while searching for the settlement site. In the rural study area, there were also individuals (mostly long-distance dispersers) that did not perform revisits and settled in the last visited area. The landscape characteristics did not explain the amount of revisits individuals made, but the amount of revisits declined with site's distance to natal nest and dispersal distance of individuals. The effect of landscape characteristics on settlement decision was small, but surprisingly, juvenile red squirrels in the rural area settled in sites with more built area compared with sites only visited. However, the decision-making of red squirrels during natal dispersal seems to be driven mainly by other factors (potentially food availability and conspecific density) than landscape characteristics. We conclude that revisiting behavior is linked to dispersal strategy of red squirrels and can differ between the sexes and habitats of the species. Significance statement Animals often choose their habitat from among multiple alternative habitats and potential settlement sites, and the decisions made during dispersal highly influence the future fitness of the animal. We examined what kind of areas juvenile red squirrels choose as their home range in both urban and rural environments and whether they display revisit behavior when selecting their home range from many alternatives. We found that search strategies during natal dispersal can vary between individuals and habitats. Surprisingly, juvenile red squirrels in the rural area settled in sites with more built area compared with the sites only visited. However, for red squirrel, decisions made by juveniles during the search of a home range are mainly influenced by other factors than landscape composition.