Responsiveness of Brown Tree Snakes to Odors

The brown tree snake (Boiga irregularis) is native to the islands of Papua New Guinea and Northern Australia. An introduced population on Guam has been implicated in the decline of that island\u27s avifauna, and the snakes regularly cause power outages on the island. Concern exists for accidental introduction on the Hawaiian Islands. Traps baited with live mice have been used in control efforts, but the logistics of maintaining live mice in the field is difficult and expensive. This study has two objectives. First, using efficacy reports of small mammal and bird feces as attractants, we set out to identify active fractions of these potential prey odor sources. If active fractions are identified, there is a possibility of encapsulating reagent grade attractant without having to process feces or urine. Second, any successful snake lure should result in the snake\u27s entry into a trap. Four snakes, 2-4 m in length, were obtained from the Philadelphia Zoo. These snakes were attracted to warm water-extracted vole and starling feces, but tended to avoid aqueous acid bird feces extracts. Snakes were indifferent to aqueous-base bird feces extracts. Snakes avoided Big Game Repellents, cadaverine, butanethiol, and ethanethiol. In summary, potential prey odors lost their attractiveness quickly upon fractionation, suggesting the overall odor profile is important for attractiveness. We are focusing efforts to encapsulate chemicals so that field operatives will not need to process raw feces. In general, sulfur- and amine-bearing volatiles seem to repel brown tree snakes, but these same compounds are attractive to mammalian carnivores. If proven true, commercially available predator odors may be used to treat potential hiding places around air cargo areas and electric power plants