USDA National Wildlife Research Center Symposia


Date of this Version

August 2007


Published in: Witmer, G. W., W. C. Pitt, and K. A. Fagerstone, editors. 2007. Managing vertebrate invasive species: proceedings of an international symposium. USDA/APHIS Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA. Also available online at


Polyvinyl chloride (PVC) tubes are effective bait stations for delivering dead neonatal mice (DNM) treated with the oral toxicant, 80 mg acetaminophen, to brown treesnakes (Boiga irregularis) in accessible jungle forest on Guam. However, PVC tubes are not practical for delivery of baits to remote areas of jungle or the forest canopy. Further, it is important that baits entangle in the canopy and not fall to the ground where they can be scavenged by non-target animals such as crabs. Data from helicopter aerial deployment of untreated DNM with radio transmitters that landed on the ground in areas of high coconut crab (Birgus latro) and hermit crab (Coenobita spp.) abundance showed that 67% of DNM were taken by crabs and 11% by monitor lizards (Varanus indicus). In contrast, in low crab abundance areas crabs took 24% of the DNM that landed on the ground. It is evident from these data that a flotation system that delivers DNM to the canopy is needed; otherwise non-target animals will remove DNM, making them unavailable for snakes. Seven aerial flotation devices were evaluated. Promising aerial devices are two types of commercial cardboard paper streamers that resulted in 75% - 85% of the DNM becoming entangled in the canopy.