How did the brown tree snake likely reach Guam and other Pacific islands?

The brown tree snake (Boiga irregularis) is believed to have reached Guam and other Pacific islands as an accidental stowaway aboard military aircraft and cargo ships.12

While some reports have suggested that the snakes were deliberately introduced to control native rodent populations, experts consider it more likely that they arrived unintentionally following the end of World War II, when Guam became a major military transfer point. Since their first sighting on Guam in 1953, these snakes have become a notorious invasive species, causing significant ecological damage by decimating native bird, lizard, and bat populations.12