title: Extreme genetic structure in a social bird species despite high dispersal capacity.
abstract: Social barriers have been shown to reduce gene flow and contribute to genetic structure among populations in species with high cognitive capacity and complex societies, such as cetaceans, apes and humans. In birds, high dispersal capacity is thought to prevent population divergence unless major geographical or habitat barriers induce isolation patterns by dispersal, colonization or adaptation limitation. We report that Iberian populations of the red-billed chough, a social, gregarious corvid with high dispersal capacity, show a striking degree of genetic structure composed of at least 15 distinct genetic units. Monitoring of marked individuals over 30 years revealed that long-distance movements over hundreds of kilometres are common, yet recruitment into breeding populations is infrequent and highly philopatric. Genetic differentiation is weakly related to geographical distance, and habitat types used are overall qualitatively similar among regions and regularly shared by individuals of different populations, so that genetic structure is unlikely to be due solely to isolation by distance or isolation by adaptation. Moreover, most population nuclei showed relatively high levels of genetic diversity, suggesting a limited role for genetic drift in significantly differentiating populations. We propose that social mechanisms may underlie this unprecedented level of genetic structure in birds through a pattern of isolation by social barriers not yet described, which may have driven this remarkable population divergence in the absence of geographical and environmental barriers.
authors.affiliation: Laboratory of Applied Ecology, Centre for Research and Technology of Agro-Environment and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801, Vila Real, Portugal.|Morinha Lab - Laboratory of Biodiversity and Molecular Genetics, Rua Dr. José Figueiredo, lote L-2, Lj B5, 5000-562, Vila Real, Portugal.
authors.forename: Francisco
authors.initials: F
authors.lastname: Morinha
authors.affiliation: Instituto de Investigación en Recursos Cinegéticos, IREC (CSIC, UCLM, JCCM), Ciudad Real, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Dávila
authors.affiliation: Laboratory of Applied Ecology, Centre for Research and Technology of Agro-Environment and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801, Vila Real, Portugal.|Department of Genetics and Biotechnology, School of Life and Environmental Sciences, University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801, Vila Real, Portugal.
authors.forename: Estela
authors.initials: E
authors.lastname: Bastos
authors.affiliation: Laboratory of Applied Ecology, Centre for Research and Technology of Agro-Environment and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801, Vila Real, Portugal.
authors.forename: João A
authors.initials: JA
authors.lastname: Cabral
authors.affiliation: National Museum of Natural Sciences (MNCN), Spanish National Research Council (CSIC), Madrid, 28006, Spain.
authors.forename: Óscar
authors.initials: Ó
authors.lastname: Frías
authors.affiliation: National Museum of Natural Sciences (MNCN), Spanish National Research Council (CSIC), Madrid, 28006, Spain.
authors.forename: José L
authors.initials: JL
authors.lastname: González
authors.affiliation: Laboratory of Applied Ecology, Centre for Research and Technology of Agro-Environment and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801, Vila Real, Portugal.
authors.forename: Paulo
authors.initials: P
authors.lastname: Travassos
authors.affiliation: Laboratory of Applied Ecology, Centre for Research and Technology of Agro-Environment and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801, Vila Real, Portugal.
authors.forename: Diogo
authors.initials: D
authors.lastname: Carvalho
authors.affiliation: National Museum of Natural Sciences (MNCN), Spanish National Research Council (CSIC), Madrid, 28006, Spain.
authors.forename: Borja
authors.identifier: http://orcid.org/0000-0002-6446-0079
authors.initials: B
authors.lastname: Milá
authors.affiliation: National Museum of Natural Sciences (MNCN), Spanish National Research Council (CSIC), Madrid, 28006, Spain.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Blanco
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D051456:Gene Flow; D040961:Genetic Drift; D014644:Genetic Variation; D005828:Genetics, Population; D018895:Microsatellite Repeats; D046109:Passeriformes / Q000235:genetics*; D012919:Social Behavior; D013030:Spain
keywords: 
  Pyrrhocorax pyrrhocorax
  ; breeding recruitment; corvid; dispersal movements; genetic differentiation; social behaviour