Effect of geomagnetic field on migratory activity in a diurnal passerine migrant, the dunnock, Prunella modularis

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Effect of geomagnetic field on migratory activity in a diurnal passerine migrant, the dunnock, Prunella modularis. / Ilieva, Mihaela; Bianco, Giuseppe; Åkesson, Susanne.

I: Animal Behaviour, Vol. 146, 2018, s. 79-85.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

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T1 - Effect of geomagnetic field on migratory activity in a diurnal passerine migrant, the dunnock, Prunella modularis

AU - Ilieva, Mihaela

AU - Bianco, Giuseppe

AU - Åkesson, Susanne

PY - 2018

Y1 - 2018

N2 - Migratory songbirds are guided by an endogenous programme during their first migration, encoding timing of migration, distance and direction. To successfully perform migration, birds have evolved phenotypic adaptations for flight, fuelling and navigation. Migratory distance in different species of birds is encoded as a period of expressed migratory restlessness, for which the length is correlated with migratory distance. Most of the work so far has been on nocturnal passerine migrants, while much less is known about the phenotypic adaptations for migration in diurnal migrants. Here we studied autumn migration fuelling and expression of migratory activity in caged diurnally migrating juvenile dunnocks in response to magnetic displacements. We kept one group (control) indoors at the location of capture in south Sweden, while the two experimental groups were gradually (over 5 days) displaced magnetically to locations to the northeast or to the wintering destination in southwest France. We found that all birds showed two peaks of activity during the day, for which the onset of activity was tightly timed to sunrise and sunset. The longest activity (2–3 h) occurred in the morning, coinciding with the natural period of migration for this species. For the control group, the migratory (flight) activity increased with the season (15 days), while it was strongly reduced for the dunnocks displaced to the wintering areas. Birds displaced to the north showed a stable, but slightly reduced migratory activity over time. The results support the finding that geomagnetic information expected to be met en route is important for triggering level of migratory activity in juveniles of a diurnal songbird migrant.

AB - Migratory songbirds are guided by an endogenous programme during their first migration, encoding timing of migration, distance and direction. To successfully perform migration, birds have evolved phenotypic adaptations for flight, fuelling and navigation. Migratory distance in different species of birds is encoded as a period of expressed migratory restlessness, for which the length is correlated with migratory distance. Most of the work so far has been on nocturnal passerine migrants, while much less is known about the phenotypic adaptations for migration in diurnal migrants. Here we studied autumn migration fuelling and expression of migratory activity in caged diurnally migrating juvenile dunnocks in response to magnetic displacements. We kept one group (control) indoors at the location of capture in south Sweden, while the two experimental groups were gradually (over 5 days) displaced magnetically to locations to the northeast or to the wintering destination in southwest France. We found that all birds showed two peaks of activity during the day, for which the onset of activity was tightly timed to sunrise and sunset. The longest activity (2–3 h) occurred in the morning, coinciding with the natural period of migration for this species. For the control group, the migratory (flight) activity increased with the season (15 days), while it was strongly reduced for the dunnocks displaced to the wintering areas. Birds displaced to the north showed a stable, but slightly reduced migratory activity over time. The results support the finding that geomagnetic information expected to be met en route is important for triggering level of migratory activity in juveniles of a diurnal songbird migrant.

KW - bird migration

KW - computer vision

KW - diurnal migration

KW - endogenous migration program

KW - fuelling

KW - geomagnetic field

KW - magnetic displacement

KW - migratory restlessness

KW - songbird

KW - Zugunruhe

U2 - 10.1016/j.anbehav.2018.10.007

DO - 10.1016/j.anbehav.2018.10.007

M3 - Article

VL - 146

SP - 79

EP - 85

JO - The British Journal of Animal Behaviour

T2 - The British Journal of Animal Behaviour

JF - The British Journal of Animal Behaviour

SN - 1095-8282

ER -