The effect of flight efficiency on gap‐crossing ability in Amazonian forest birds

The ability to move across the landscape is a fundamental property of species that can determine their chances of persistence in fragmented landscapes and in rapidly changing environments. Despite its importance, empirical evidence showing the effect of movement capacity on patterns of movement across fragmented landscapes is limited. In this study, we examine the role of flight efficiency on the likelihood of crossing a man-made habitat gap. We used data from the Biological Dynamics of Forest Fragments Projects on recaptures of banded birds in an Amazonian forest bisected by a road. For a total of 45 species, we estimated flight efficiency using the hand-wing index (a proxy for the wing's aspect ratio) and used it as a predictor of the probability of road crossing in phylogenetic binomial regression models. We found that flight efficiency was a strong predictor of road-crossing probability: species with high hand-wing indices crossed the road more frequently than those with low hand-wing indices. In contrast, other characteristics such as body mass, diet, flocking behavior, and foraging stratum did not show significant associations with road-crossing probability. Our results suggest that proxies of flight efficiency such as the hand-wing index can be powerful tools for predicting the vulnerability of bird species to forest fragmentation. Abstract in Spanish is available with online material