Why do birds ... winter where they do?

When migratory birds travel to wintering grounds, what factors determine where they decide to stay? Some birds are known to follow their niches and travel to areas with climates similar to their native breeding grounds, while others prefer climates that are very different. This study presents an analysis of the monthly climatic variation of the distribution of 13 neotropical migratory birds throughout the winter season. Using GBIF-mediated occurrences and climatic data, researchers constructed monthly ecological nice models for each of the species, and their results indicate that the selection of wintering sites is driven mainly by temperature and levels of precipitation. The models also show that distributions in the early winter months vary less than late months, suggesting that the birds who arrive first, will occupy the sites with optimal climate conditions, leaving suboptimal sites to late-comers.