Brown Tree Snake Response to Visual and Olfactory Cues

The brown tree snake (Boiga irregularis), an exotic on Guam, is primarily an arboreal colubrid thought responsible for the decline and extinction of many species. Brown tree snakes on Guam currently are trapped, with live mice as lures, to minimize the likelihood of the snakes being transported elsewhere. It is desirable to end the use of live mice in traps, but the successful development of inanimate lures requires initial knowledge about snake foraging behavior. I tested whether visual or chemical cues most stimulate appetitive behavior in brown tree snakes, and I examined the effectiveness of artificial lures for capturing snakes. Using trials in both a laboratory and field setting, I determined that both visual and olfactory cues were important for trapping brown tree snakes. The effectiveness of live mice as a lure greatly diminished with the loss of either sensory cue, apparently because of synergy between combined cues. Development of simple artificial lures based on the cues provided by live mice is likely to be difficult. Lures based on cues associated with live mice may require complex odor and visual stimuli; however, odors from other sources may lure snakes without a visual stimulus.