Data from: Metapopulation-level analyses reveal positive fitness-consequences of immigration in a small bird

Dispersal links eco-evolutionary dynamics of subpopulations in fragmented
landscapes and may play a crucial role in the viability of populations by
increasing individual fitness and subpopulation growth rates. However,
knowledge of the individual fitness of immigrants and residents and their
offspring at the local and metapopulation levels is often lacking due to
the difficulty of quantifying fitness in geographically structured wild
populations, which requires extensive field efforts. A comprehensive
dataset that includes more than 15 years of individual
capture-mark-recapture information and a high-resolution SNP-based
pedigree from an insular wild house sparrow (Passer domesticus)
metapopulation, was used to examine the fitness consequences of successful
immigration for parent and offspring generations and assess the relative
contributions of immigrants and residents to a local pool of recruits
versus individuals that recruited in other populations within the
metapopulation. We showed that immigrants produced more recruiting
offspring annually and during their lifetime than residents. Moreover, we
found that hybrid recruits (produced by immigrant-resident parents) had
higher adult survival and produced more recruiting offspring during their
lifetime than recruits produced by two resident or two immigrant parents.
Additionally, although contributions to the local pool of recruits did not
differ between immigrant and resident parents during their lifetime,
immigrant parents produced more offspring recruited in other populations
than resident parents. Our results indicate that the benefits of being an
immigrant last at least through the first offspring generation. Such
positive fitness effects of immigrants may improve local population
viability as well as metapopulation viability. Our study shows the
importance of quantifying the fitness of successful immigrants at a wide
geographic scale in structured populations, because it may be difficult to
a priori predict whether dispersers and residents contribute similarly or
differently to the dynamics at local population and metapopulation levels.