Exploring broad-scale songbird migration patterns in Cuba and the Yucatan Peninsula to inform international conservation priorities

Mexico’s Yucatan Peninsula and Cuba offer the first available stopover sites where songbirds can rest, refuel, or escape unfavorable weather following passage across the Gulf of Mexico in the fall. While large numbers of songbirds migrate through the region, the scarcity of standardized, constant effort survey data has hindered our understanding of broad-scale spatial patterns in species’ abundances, age ratios, and energetic condition in the southern Gulf. Documentation of species-and age-specific migration routes and the identification of areas used by birds in poor physical condition are necessary for developing effective conservation strategies. In fall 2015 we initiated a collaborative, international effort to simultaneously survey migratory birds on Contoy Island, northeast of Cancun, Mexico and the Guanahacabibes Peninsula (GP) in southwestern Cuba. Together with comparable data previously collected in the Ria Lagartos Biosphere Reserve (RLBR) along the northern Yucatan Peninsula coast, we explored spatial patterns in bird abundance, age ratios and body condition. Overall, we found that capture rates were higher in RLBR and GP than Contoy. Some species’ capture rates increased toward the east while others decreased. Birds caught on Contoy were significantly leaner and younger than those in RLBR and GP. Based on findings from other studies, Contoy is a low-quality site that provides emergency resting opportunities for en route songbirds, which can explain some of the results found in our study. We discuss how these spatial patterns can inform coordinated regional and international conservation efforts to promote the successful migration of songbirds through the southern Gulf Basin.