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The factors responsible for variation in dispersal distances across species remain poorly understood. Previous comparative studies found differing results and equivocal support for theoretical predictions. Here I re‐examine factors that influence natal dispersal distances in British birds while taking into account the cost of transport as estimated from proxies of long‐distance flight efficiency. First, I show that flight efficiency, as estimated by the hand‐wing index, the aspect ratio, or the lift‐to‐drag ratio, is a strong predictor of dispersal distances among resident species. Most migratory species showed a similar pattern, but a group of species with relatively low aerodynamic efficiency showed longer‐than‐expected dispersal distances, making the overall trend independent of flight efficiency. Ecological, behavioral, and life history factors had a small or nil influence on dispersal distances, with most of their influence likely …