Abstract Globally, species are changing their ranges poleward and uphill due to climate warming. This poses a particular risk to biodiversity endemic to islands, where elevational range changes can result in a smaller area of suitable habitat. We analysed point-count data of forest birds on a small Caribbean island with dynamic occupancy models to gather robust evidence of elevational range changes. We found evidence for range changes in five out of 12 species, with four species changing uphill, including the endemic Montserrat Oriole (Icterus oberi), and one species showing a range contraction towards lower elevations. The files in this repository contain the data and analytical code to replicate the results of the publication in Journal of Biogeography (DOI: 10.1111/jbi.70223). The version contained in this repository does not include updates and improvements that occurred after 31 March 2026.