learning certain behaviors (wheel spinning and lever 

 pressing), using a food-pellet reward system. Rats 

 required about 14 sessions to reach a steady-state 

 performance in wheel trials but at least 21 sessions 

 during the lever-pressing trials. Considerable variation 

 in individual behavior was noted. Researchers 

 concluded that individual activity levels may influence 

 exploratory behavior, which may be correlated to the 

 likelihood of rats' entering traps or bait stations used 

 in detection and control efforts. It is possible that 

 multiple detection devices will need to be employed to 

 assure detection of newly arriving rats on an island. 



absence of many introduced threats and usually 

 respond poorly to invasive animals or disease. 



Invasive species are the single greatest threat 

 to Hawaii's agricultural economy and natural 

 environment and to the health and lifestyle of its 

 people. Invasive species cause millions of dollars' 

 worth of crop losses, the extinction of native 

 species, the destruction of native forests, and 

 the spread of disease and also reduce the health 

 and safety of residents. This project investigates 

 a variety of methods to resolve small-mammal 

 damage to agriculture, reforestation, and structures 

 and equipment. 



Scientists are studying rodent learning behaviors in order to 

 better detect invading rats on islands. 



TITLE: Methods and Strategies To Manage 



Invasive Species Impacts to Agriculture in 

 Hawaii 



GOAL: Develop safe and effective methods and 



strategies to manage the effects of invasive 

 species on agriculture, natural resources, 

 and human health and safety in Hawaii and 

 other island ecosystems. 



Oceanic islands like the Hawaiian chain are more 

 susceptible to invasive species than mainland areas 

 because islands have few predators or competitors, 

 have a lot of air and sea traffic, and typically provide 

 a favorable climate for many species. Furthermore, 

 native species on the islands have evolved in the 



Rodenticide Development — The efficacy of many 

 commercially available rodenticide products 

 on wild black rats (Rattus rattus), Polynesian 

 rats (R. exulans), and mice (Mus musculus) is 

 unknown. The few successfully used products 

 have not been systematically tested in a common 

 laboratory environment or compared to other 

 available products. Products vary according to their 

 toxicity to nontarget animals, speed and method of 

 action, and bioaccumulation and biomagnification 

 potential. Thus, a product appropriate for one 

 application may not be appropriate for another, 

 and limiting the pool of potential products restricts 

 a manager's ability to mitigate the effects of an 

 eradication effort. Two major data gaps are the 



Polynesian rat. 



32 Developing Methods 



