Understanding determinants of home range behaviour of feral cats as introduced apex predators in insular ecosystems: a spatial approach

Behav Ecol Sociobiol (2013) 67:19711981 DOI 10.1007/s00265-013-1605-7

ORIGINAL PAPER

Understanding determinants of home range behaviour of feral cats as introduced apex predators in insular ecosystems:a spatial approach

Mariano R. Recio & Philip J. Seddon

Received: 20 April 2013 /Revised: 6 July 2013 /Accepted: 8 July 2013 /Published online: 30 July 2013 # Springer-Verlag Berlin Heidelberg 2013

Abstract The introduced feral cat (Felis catus) is a widespread generalist with flexible social behaviour and an apex predator without major interspecific competitors in insular ecosystems that evolved in the absence of predators. Mechanistic definitions consider an animals home range to be the spatial expression of a cognitive map that is kept up-to-date with the status of critical resources that contribute to animal fitness. We assumed there are two major determinants structuring the home range of cats as apex predators in insular ecosystems: the distribution of critical food resources and conspecific distribution. We hypothesized that cats structure their home ranges by optimizing the use of staple critical food resources and that as a consequence of the presence of rich resources cats tend to socialise, aggregate and share space. We carried out spatial analyses using location data for feral cats tracked using lightweight GPS collars in conjunction with the suitability value of rabbit patches and their associated ownership costs for cats within a New Zealand braided-river environment. Cat home ranges and spatial distribution, especially for females, were related to the inclusion of rabbit patches within home ranges with higher mean value than the average of neighbourhood patches in the landscape. Cats showed solitary behaviour but tolerance to conspecific presence by sharing high-use areas and high-value rabbit patches, mostly at different times, resulting in occasional encounters among males and females. Home range size and patterns of spatial overlap were dependant on sex and season.

Solitary spacing patterns as consequence of innate preferences together with resource constraints may regulate feral cat population densities.

Keywords Spatial cognitive map . Home range . Resources . Intraspecific relationships . Interactions . Social behaviour . Feral cats . Insular ecosystems

Introduction

Home range definitions have varied from the classic idea as the area traversed by an individual animal during its normal activities (Burt 1943) to more recent conceptions such as the one considering it as the...