Altitudinal migration in resident Greater Antillean birds

Altitudinal migration, as a seasonal phenomenon, has become more documented in recent years in tropical resident avifauna. Despite these advances, little is known about to what extent this aspect of avian phenology is present in island ecosystems. Many islands have elevational gradients where, anecdotally, birds are present at some altitudes only on a seasonal basis. Given the unevenness of habitat disturbance on Caribbean islands, fully understanding life history cycles is imperative for implementing adequate conservation plans. In order to test the hypothesis that residential birds migrate seasonally along an altitudinal gradient, we examine species occupancy patterns using eBird data and USGS elevational maps for the islands of Cuba, Hispaniola, Jamaica, and Puerto Rico. We analyze species from spatial and taxonomic perspectives to understand whether species’ elevational range shifts are influenced more by evolutionary history or island topography. Furthermore, we analyze patterns inherent within eBird data to determine to what extent elevational and temporal biases are present in the available observational data, and attempt to assess the extent to which eBird data can be used to model, monitor, and analyze Caribbean bird populations.