Sex-specific fitness correlates of dispersal in a house sparrow metapopulation.

1. Dispersal affects many important ecological and evolutionary processes. Still, little is known about the fitness of dispersing individuals. 2. Here, we use data from a long-term study of a house sparrow Passer domesticus metapopulation to compare lifetime reproductive success (LRS) of resident and immigrant individuals, all with known origin. 3. Lifetime production of recruits by immigrant males was much lower than for resident males, because of shorter life span and lower annual mating success. In contrast, lifetime production of recruits did not differ significantly between immigrant and resident females. 4. Over their lifetime, dispersers contributed fewer recruits to the local population than residents. This shows that immigrant house sparrows have different, sex specific, demographic effects on the population dynamics than residents.