Wind selectivity of migratory flight departures in birds
Författare
Summary, in English
Optimal migration theory predicts that birds minimizing the overall time of migration should adjust stopover duration with respect to the rate of fuel accumulation. Recent theoretical developments also take into account the wind situation and predict that there is a time window (a set of days) during which birds should depart when assisted by winds but will not do so if there are head winds. There is also a final day when birds will depart irrespective of wind conditions. Hence, the wind model of optimal migration theory predicts that birds should be sensitive to winds and that there should be a correlation between departures and winds blowing towards the intended migration direction. We tested this assumption by tracking the departures of radio-tagged passerines during autumn migration in southern Sweden. Our birds were moderately to very fat when released and therefore energetically ready for departure. There was a significant correlation between direction of departure and wind direction. We also found that during days when birds departed there was a significantly larger tail wind component than during days when birds were present but did not depart. Our results show that passerines do take the current wind situation into account when departing on migratory flights. We also briefly discuss possible clues that birds use when estimating wind direction and strength. The inclusion of wind is an important amendment to optimal migration theory of birds and should be explored further.
Avdelning/ar
Publiceringsår
2000
Språk
Engelska
Sidor
140-144
Publikation/Tidskrift/Serie
Behavioral Ecology and Sociobiology
Volym
47
Issue
3
Dokumenttyp
Artikel i tidskrift
Förlag
Springer
Ämne
- Biological Sciences
Status
Published
Forskningsgrupp
- Animal Flight Lab
- Animal Navigation Lab
ISBN/ISSN/Övrigt
- ISSN: 1432-0762