The effect of phenotypic traits and external cues on natal dispersal movements

Authors

  • María del Mar Delgado,

    Corresponding author
    1. Department of Conservation Biology, Estación Biológica de Doñana, CSIC, c/Americo Vespucio s/n, 41092 Seville, Spain
    2. Laboratory of Ecological and Evolutionary Dynamics, Department of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland
      Correspondence author. E-mail: mmdelgado@ebd.csic.es
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  • Vincenzo Penteriani,

    1. Department of Conservation Biology, Estación Biológica de Doñana, CSIC, c/Americo Vespucio s/n, 41092 Seville, Spain
    2. Finnish Museum of Natural History, University of Helsinki, FI-00014 Helsinki, Finland
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  • Eloy Revilla,

    1. Department of Conservation Biology, Estación Biológica de Doñana, CSIC, c/Americo Vespucio s/n, 41092 Seville, Spain
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  • Vilis O. Nams

    1. Department of Environmental Sciences, Nova Scotia Agricultural College, Box 550, Truro, Canada NS B2N 5E3
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Correspondence author. E-mail: mmdelgado@ebd.csic.es

Summary

1. Natal dispersal has the potential to affect most ecological and evolutionary processes. However, despite its importance, this complex ecological process still represents a significant gap in our understanding of animal ecology due to both the lack of empirical data and the intrinsic complexity of dispersal dynamics.

2. By studying natal dispersal of 74 radiotagged juvenile eagle owls Bubo bubo (Linnaeus), in both the wandering and the settlement phases, we empirically addressed the complex interactions by which individual phenotypic traits and external cues jointly shape individual heterogeneity through the different phases of dispersal, both at nightly and weekly temporal scales.

3. Owls in poorer physical conditions travelled shorter total distances during the wandering phase, describing straighter paths and moving slower, especially when crossing heterogeneous habitats. In general, the owls in worse condition started dispersal later and took longer times to find further settlement areas. Net distances were also sex biased, with females settling at further distances. Dispersing individuals did not seem to explore wandering and settlement areas by using a search image of their natal surroundings. Eagle owls showed a heterogeneous pattern of patch occupancy, where few patches were highly visited by different owls whereas the majority were visited by just one individual. During dispersal, the routes followed by owls were an intermediate solution between optimized and randomized ones. Finally, dispersal direction had a marked directionality, largely influenced by dominant winds. These results suggest an asymmetric and anisotropic dispersal pattern, where not only the number of patches but also their functions can affect population viability.

4. The combination of the information coming from the relationships among a large set of factors acting and integrating at different spatial and temporal scales, under the perspective of heterogeneous life histories, are a fruitful ground for future understanding of natal dispersal.

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