title: Migratory connectivity and population-specific migration routes in a long-distance migratory bird.
abstract: Knowledge about migratory connectivity, the degree to which individuals from the same breeding site migrate to the same wintering site, is essential to understand processes affecting populations of migrants throughout the annual cycle. Here, we study the migration system of a long-distance migratory bird, the Montagu's harrier Circus pygargus, by tracking individuals from different breeding populations throughout northern Europe. We identified three main migration routes towards wintering areas in sub-Saharan Africa. Wintering areas and migration routes of different breeding populations overlapped, a pattern best described by 'weak (diffuse) connectivity'. Migratory performance, i.e. timing, duration, distance and speed of migration, was surprisingly similar for the three routes despite differences in habitat characteristics. This study provides, to our knowledge, a first comprehensive overview of the migration system of a Palaearctic-African long-distance migrant. We emphasize the importance of spatial scale (e.g. distances between breeding populations) in defining patterns of connectivity and suggest that knowledge about fundamental aspects determining distribution patterns, such as the among-individual variation in mean migration directions, is required to ultimately understand migratory connectivity. Furthermore, we stress that for conservation purposes it is pivotal to consider wintering areas as well as migration routes and in particular stopover sites.
authors.affiliation: Dutch Montagu's Harrier Foundation, , PO Box 46, Scheemda 9679 ZG, The Netherlands, Animal Ecology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, , PO Box 11103, Groningen 9700 CC, The Netherlands, Behavioural Ecology and Self-organization, Centre for Ecological and Evolutionary Studies, University of Groningen, , PO Box 11103, Groningen 9700 CC, The Netherlands, Institute of Avian Research 'Vogelwarte Helgoland', , An der Vogelwarte 21, Wilhelmshaven 26386, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Trierweiler
authors.forename: Raymond H G
authors.initials: RH
authors.lastname: Klaassen
authors.forename: Rudi H
authors.initials: RH
authors.lastname: Drent
authors.forename: Klaus-Michael
authors.initials: KM
authors.lastname: Exo
authors.forename: Jan
authors.initials: J
authors.lastname: Komdeur
authors.forename: Franz
authors.initials: F
authors.lastname: Bairlein
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Koks
mesh_terms: D025041:Animal Migration; D000818:Animals; D003247:Conservation of Natural Resources; D046093:Falconiformes / Q000502:physiology*; D005843:Geography; D011157:Population Dynamics; D012621:Seasons; D012726:Sexual Behavior, Animal
keywords: bird migration strategies; conservation; migration speed; raptor bird; satellite tracking; spatial scale