These data represent brown treesnake (Boiga irregularis) captures from a population in a 5 ha natural snake enclosure on Guam from 2016 - 2023. During the period of study we artificially reduced the number of snakes present in the population through a variety of control tools that included toxic baits, as mice and chicks, live trapping, and hand capture. We censused the population intensively during the entire period of study during nocturnal visual surveys. During those surveys we also counted the number of lizards, rodents, and birds that were seen. Thus, we have absolute numbers of snakes based on mark-recapture methods and capture-per-unit-effort based on sightings of all taxonomic groups. These data are specifically processed to provide monthly estimates of numbers of brown treesnakes relative to the average sightings per unit effort of rodents, lizards, and birds. Brown treesnakes are an invasive species that has had detrimental impacts on almost all native vertebrate on Guam. Raw data used to generate estimates are available in an affiliated data release.