Differential timing of spring migration in northern wheatears Oenanthe oenanthe: hurried males or weak females? (original) (raw)

Abstract

In a field experiment on the island of Helgoland (southeast North Sea), we investigated whether migration strategy or competition between the sexes cause the differential timing of spring migration of male and female northern wheatears (Oenanthe oenanthe) (males migrating earlier). The study included two subspecies, heading towards Greenland/Iceland and Scandinavia, respectively, and is based on colour-ringing and remote weighing of individuals. Despite food offered ad libitum, most Scandinavian birds left the island on the day of arrival or stayed only 1–3 days, whereas more than half of Greenlandic/Icelandic birds stayed for up to 12 days and refuelled rapidly. In the latter subspecies, males showed a positive correlation of departure fuel load and fuel deposition rate, resembling time-minimizers in optimal migration theory. In contrast, females departed irrespective of fuel deposition rate, with an approximately constant level of fuel stores. This level was lower than in males, but sufficient to enable by-passing of stopover sites en route, allowing us to regard females as time-minimizers also. Since females are not able to reach Greenland without additional refuelling elsewhere and males appeared to have a larger potential for by-passing stopover sites, time-selection seems to be more pronounced in males and may be the reason for earlier migration of males. Intraspecific aggressive interactions between colour-ringed birds were predominantly won by the initiator, by males and by larger birds, whereas fuel load and subspecies did not affect the outcome. Although compared to females, males were more often dominant at the feeding stations or held territories, refuelling patterns could not be explained by dominance. Subordinate or non-territorial birds did not refuel at a lower rate or depart with lower fuel loads than dominant or territorial birds. In non-territorial birds, the restricted access to feeding stations was made up with larger doses of food taken per visit, leading to the same energy intake as that of dominant and territorial birds. Therefore, competition during stopover could be eliminated as the reason for differential timing of migration of male and female wheatears, but this result may be species-specific.

Access this article

Log in via an institution

Subscribe and save

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

Download references

Acknowledgements

Assistance during the field work was provided by R. Morgenstern and A. Walter. Technical support was obtained from R. Nagel. We are much indebted to F. Bairlein for initiating the study. He, N. Anthes, L. Jenni and an anonymous referee commented on the manuscript. The study was financially supported by the “Freunde und Förderer der Inselstation der Vogelwarte Helgoland e.V.” and by the Deutsche Forschungsgemeinschaft (BA 816/15-1). The experiments comply with the current laws of Germany and Schleswig-Holstein.

Author information

Author notes

  1. Volker Dierschke
    Present address: University of Kiel, Forschungs- und Technologiezentrum Westküste, 25761 , Büsum, Hafentörn, Germany
  2. Bettina Mendel
    Present address: University of Kiel, Forschungs- und Technologiezentrum Westküste, 25761 , Büsum, Hafentörn, Germany
  3. Heiko Schmaljohann
    Present address: Ornithological Institute, 6204 , Sempach, Switzerland

Authors and Affiliations

  1. Institute for Avian Research “Vogelwarte Helgoland”, Inselstation Helgoland, Postfach 1220 , 27494, Helgoland, Germany
    Volker Dierschke, Bettina Mendel & Heiko Schmaljohann

Authors

  1. Volker Dierschke
    You can also search for this author inPubMed Google Scholar
  2. Bettina Mendel
    You can also search for this author inPubMed Google Scholar
  3. Heiko Schmaljohann
    You can also search for this author inPubMed Google Scholar

Corresponding author

Correspondence toVolker Dierschke.

Additional information

Communicated by W. Wiltschko

Rights and permissions

About this article

Cite this article

Dierschke, V., Mendel, B. & Schmaljohann, H. Differential timing of spring migration in northern wheatears Oenanthe oenanthe: hurried males or weak females?.Behav Ecol Sociobiol 57, 470–480 (2005). https://doi.org/10.1007/s00265-004-0872-8

Download citation

Keywords