Physical and behavioural abilities of commensal rodents related to the design of selective rodenticide bait stations

Abstract

Design of selective bait stations to deliver rodenticide bait is often proposed for management of non-target animal access, but much of the information on the behavioural and physical capabilities of rodents relative to station access has not been readily available or is based on unpublished, informal observations or anecdotes repeated for many years. We studied the climbing and jumping abilities of Polynesian Rats (Rattus exulans), Norway Rats (R. norvegicus), Roof Rats (R. rattus), and House Mice (Mus musculus), focused on applications for eradication of these invasive rodents from island ecosystems in the Pacific where a variety of important non-target animals occur. The maximum jumping heights achieved by the three rat species was 40 cm; House Mice jumped a maximum of 25 cm. The minimum diameter holes through which these species could pass were 40 mm (Norway Rats), 35 mm (Roof Rats), 30 mm (Polynesian Rats), and 13 mm (House Mice). Our findings establish threshold differences for these species for transiting access openings or jumping to platforms to obtain food. In areas where endangered birds or other animals occur, such information could be used in designing selective stations so as to prevent unnecessary poisoning.

Keywords:

• bait station
• rodenticide
• rodent behaviour
• rodent control
• rodent eradication

Acknowledgements

This research was funded by the National Wildlife Research Center, USDA/APHIS/Wildlife Services as Protocol QA 1264. Institutional Animal Care and Use Committee approval was received March 25, 2005. We thank Gary W. Witmer for assistance with protocol development, Rogelio E. Doratt for assistance with data analysis, and Michael W. Fall for assistance with report preparation and for helpful discussion of rat behaviour. Comments by Peter Dunlevy and an anonymous reviewer helped us improve the manuscript.