Fritts, T.H. and G.H. Rodda. unknownyear. Invasions of the brown tree snake. http://ace1.ma.utexas.edu/users/davis/375/LECTURES/L24/snake3.pdf accessed 18 January 2011.
Around 1950, populations of the brown tree snake (Boiga irregularis) were introduced on Guam, a previously snake-free island. This introduction was the result of post-World War II traffic carrying military materials from the South Pacific region (Savidge 1987; Rodda et al. 1992). It resulted in major ecological changes and the loss of several bird and lizard species from the island starting in the 1970s and extending to the late 1980s. The severity of ecological damages resulting from this introduced snake may have been increased by the presence of other nonindigenous species, which served as alternative prey as native species declined. The brown tree snake dispersed throughout Guam in the 1950s, 1960s, and 1970s, reaching high populations that resulted in devastating levels of predation on most native and introduced vertebrates (Savidge 1987; Engbring and Fritts 1988; Rodda et al. 1992). At the peak of the snake's irruption on Guam, densities probably exceeded 100 snakes/ha (40 snakes/acre), but following depletion of many of Guam's birds and mammals, snake densities appear to have fallen to 20-50 snakes/ha (8-20 snakes/acre; Rodda et al. 1992). In the face of the loss of native forest birds and drastic reductions in other bird, mammal, and reptile species, the snake subsisted on smaller lizard prey and on introduced species, including lizards (Hemidactylus frenatus and Carlia cf. fusca), domestic poultry and cage birds, rodents (Rattus spp. and Mus musculus), house shrews (Suncus murinus), Eurasian tree sparrows (Passer montanus), and Javanese turtle doves (Streptopelia bitorquata). Thus, the reduction of snake densities that might have been expected after the loss of native prey species was limited because the snake could subsist on alternative introduced prey.