Space use of suburban pileated woodpeckers (Dryocopus pileatus): insights on the relationship between home range, core areas, and territory.

Home range, territory, and core areas are concepts that have been used to describe a species' space use. However, little research has been done to understand potential spatial relationships between them. While the relative importance of different areas of the home range has been addressed with utilization distributions, there is a lack of such analysis for territories. We mapped the locations of territorial advertisements (calls and drumming) of the pileated woodpecker in suburban areas to determine a more objective, behavior-based approach to define areas of importance within territories, which we called 'highly-defended areas'. We then analyzed the relationship between such highly-defended areas and a bird's home range and territory. On average, territories represented 69.6 ± 0.06% (mean ± SE) of a woodpecker's home range, and highly-defended areas were 34.3 ± 0.03% of their home range. Highly-defended areas objectively determined the portion of the territory that was important for fitness. For example, they contained a significant proportion of the nests and roost sites of pileated woodpeckers, which are important for reproduction and survivorship. This approach could be useful to further incorporate behavior in the study of the spatial ecology of species.