New Zealand Journal of Ecology (2011) 35(2): 193- 193

Random exploratory behaviour by individual island colonists

Conference Abstract
James C. Russell  
Angus J. C. McMorland  
Jamie W. B. MacKay  
  1. Landcare Research, PO Box 40, Lincoln 7640, New Zealand

The post-arrival behaviour of individuals in novel environments influences survival and population establishment. For pest species early detection and elimination of new arrivals is vital to prevent invasion, and this requires a thorough understanding of movement patterns post-arrival. Studies have previously investigated exploratory movements in novel laboratory environments, but not during colonization of natural systems. We individually released five adult male brown rats (Rattus norvegicus) onto a rat-free island and monitored their movements hourly for three weeks. We demonstrate that (i) in the period immediately following arrival individual movements are apparently random; (ii) individuals effectively remain around their release site for three days before dispersing further; (iii) range size is much larger compared to individuals at high-density; (iv) exploration rate is mediated by central place foraging behaviour. These low-density movement behaviours have implications for understanding animal colonization dynamics, and intercepting wide-ranging individuals of invasive species as they arrive at new locations.