The Effect of Feeder Hotspots on the Predictability and Home Range Use of a Small Bird in Winter

Resource distributions may be important for spatial use in animals. There appears to be a negative relationship between resource quality or density and home range size (McNab 1963; e.g. Dussault et al. 2005), and moreover, the distribution of resources within a home range may also affect its overall shape (Mitchell & Powell 2004). All else equal, the more resources that are available, the less area an animal may need to use to access a suitable number of those resources. Territoriality, however, may complicate this effect (Maher & Lott 2000), making spatial use more a function of individual interactions than resources per se (Adams 2001). Few, however, have considered how predation risk and resource distribution might interact to affect animal movement patterns and overall spatial use (e.g. Jensen et al. 2005), especially in non-territorial species. Recent theory predicts that predators should use resource hotspots (point sources of abundant resources), whereas prey should avoid areas where predators are abundant (Hugie & Dill 1994; Sih 1998). This perspective, however, does not fully consider movement as a behavioral strategy (Sih 2005; but see Hammond et al. 2007), but rather considers movement to be dangerous for prey (e.g. Werner & Anholt 1993; Lima 1998). While this may be the case at a small scale (Lima 1998), the wholesale application of this idea to larger spatial scales reduces risk to a constant probability in homogeneous space. As behavioral interactions between predators and prey can be dynamic (reviewed by Lima 2002 and Sih 2005), the movement patterns of both predators and prey, the predictability of that movement may be important (Mitchell & Lima 2002). In a situation where both predators and prey can learn and move among different patches, a shell Correspondence Timothy C. Roth II, Department of Biology, University of Nevada, Reno, NV 89557, USA. E-mail: [email protected]