Sökning: "bird ringing"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden bird ringing.

  1. 1. Individual consistency in bird migration

    Författare :YANNIS VARDANIS; Evolutionär ekologi; []
    Nyckelord :bird migration; telemetry; bird ringing; individual consistency; repeatability; site fidelity; routes; timing; annual cycle; meta-analysis;

    Sammanfattning : Slight differences, which appear in the individual animals of the same species and population have been recognised and appreciated ever since Darwin. These consistent intra-specific differences in animals have been considered very important because they are often inherited, and thus, provide the basic material for evolution to act on. LÄS MER

  3. 2. Climate change effects on migratory birds and on the ecology and behaviour of the willow warbler (Phylloscopus trochilus)

    Författare :Johanna Hedlund; Sven Jakobsson; Thord Fransson; Cecilia Kullberg; Sara Cousins; Martin Schaefer; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; climate change; bird migration; ecology; phenology; bird; avian; willow warbler; chaffinch; land use change; landscape ecology; historical ecology; etologi; Ethology;

    Sammanfattning : Recent global climate change is influencing the behaviour and ecology of species worldwide. Birds are typical systems to study in this context, as they are often migratory and thus subjected to a variety of environmental effects. LÄS MER

  4. 3. On the importance of farmland as stopover habitat for migrating birds

    Författare :Juliana Dänhardt; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; conservation; bird migration; agriculture; stopover ecology; Golden plover; Pluvialis apricaria; landscape heterogeneity; organic farming; food availability; earthworms;

    Sammanfattning : Agricultural intensification has led to dramatic population declines among many farmland bird species. Negative effects of intensive farming in terms of decreased local habitat quality or structural simplification of farmland landscapes have reduced both reproductive outcome and winter survival of many species. LÄS MER

  5. 4. Flight Behaviour of Passerines on Nocturnal Migration

    Författare :Cecilia Nilsson; Evolutionär ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Bird migration; Passerines; Flight Behaviour; Tracking radar; Optimal migration; Flight speed; Airspeed; Wind drift; Nocturnal migration; Coastline effects; Flight directions; Reverse migration;

    Sammanfattning : Many passerines migrate during the night and at high altitudes, making their migration difficult to observe. By using tracking radars we have been able to make exact observations of the flight behaviour of passerines on nocturnal migration, which has enabled us to test several hypotheses about adaptive values and constraints regarding migratory behaviour in different ecological contexts. LÄS MER

  7. 5. Differential migration in raptors

    Författare :Nils Kjellén; Biodiversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Osprey; Skua; Population monitoring; Bird migration; Satellite telemetry; Animal ecology; Djurekologi;

    Sammanfattning : Differences between ages, sexes and populations in the timing of migration at Falsterbo, Sweden and in the choice of wintering site among raptors in Scania were investigated. Competition and dominance is the best primary explanation to the results. LÄS MER