These data address experimental evaluations of dietary preference by captive brown treesnakes on Guam. Snakes were collected from the wild in areas with birds present and in areas without birds present 2018–2019. Snakes were then run through preference trials during which they were offered first live lures (mouse and finch) in snake traps on opposite sides of the arena. On the second night, snakes were offered dead carrion (baits) of each prey type (mouse, chicken chick) equal to 30% of their mass. Choices were monitored overnight using game cameras and then transcribed the following day. Individuals were classified as BIRD or NOBIRD snakes based on whether they had birds in their gut contents at the time of capture. Interest in bird or mouse prey was quantified by which trap they entered (mouse or finch), number of times they investigated each trap, which bait they ate (mouse or chick) and number of times they investigated the bait or mouse.