Departure directions, migratory timing and non-breeding distribution of the Red-backed Shrike Lanius collurio: do ring reencounters and light-based geolocator data tell the same story?

TY - JOUR

T1 - Departure directions, migratory timing and non-breeding distribution of the Red-backed Shrike Lanius collurio

T2 - do ring reencounters and light-based geolocator data tell the same story?

AU - Korner-Nievergelt, Fränzi

AU - Jenni, Lukas

AU - Tøttrup, Anders Peter Them

AU - Pasinelli, Gilberto

PY - 2012/12

Y1 - 2012/12

N2 - This study explores differences and consistencies between ring re-encounter and light-based geolocator data from Red-backed Shrike when used for studying three aspects of bird migration: departure direction and its relationship with longitude and latitude, non-breeding distribution, and timing of migration. Departure directions were consistent between the Iwo methods. They indicate a funnel-shaped migration with individuals from southwest Europe taking a detour via the eastern Mediterranean rather than migrating via Gibraltar. This indicates that an original migration route has been retained after colonisation of the breeding range. Non-breeding distributions differed substantially between birds ringed and re-encountered and birds tracked by geolocators. This difference may be due to spatiotemporal heterogeneity in ring re-encounter probability and/or due to the two samples of birds belonging to different populations. The monthly average ring re-encounter location moved later southward during autumn and earlier northward during spring migration than the geolocator positions, because of an over-representation of re-encounters in the north. The results emphasise the importance of combining different sources of data when analysing migration patterns of animals that are difficult to track.

AB - This study explores differences and consistencies between ring re-encounter and light-based geolocator data from Red-backed Shrike when used for studying three aspects of bird migration: departure direction and its relationship with longitude and latitude, non-breeding distribution, and timing of migration. Departure directions were consistent between the Iwo methods. They indicate a funnel-shaped migration with individuals from southwest Europe taking a detour via the eastern Mediterranean rather than migrating via Gibraltar. This indicates that an original migration route has been retained after colonisation of the breeding range. Non-breeding distributions differed substantially between birds ringed and re-encountered and birds tracked by geolocators. This difference may be due to spatiotemporal heterogeneity in ring re-encounter probability and/or due to the two samples of birds belonging to different populations. The monthly average ring re-encounter location moved later southward during autumn and earlier northward during spring migration than the geolocator positions, because of an over-representation of re-encounters in the north. The results emphasise the importance of combining different sources of data when analysing migration patterns of animals that are difficult to track.

U2 - 10.1080/03078698.2012.748508

DO - 10.1080/03078698.2012.748508

M3 - Journal article

SN - 0307-8698

VL - 27

SP - 83

EP - 93

JO - Ringing and Migration

JF - Ringing and Migration

IS - 2

ER -