1Present address: Centre for Ecology and Hydrology Banchory, Hill of Brathens, Banchory, Aberdeenshire, AB31 4BW, United-Kingdom.
Contrasting responses of migration strategies in two European thrushes to climate change
Article first published online: 27 OCT 2006
Global Change Biology
Volume 13, Issue 1, pages 275–287, January 2007
How to Cite
RIVALAN, P., FREDERIKSEN, M., LOL̈S, G. and JULLIARD, R. (2007), Contrasting responses of migration strategies in two European thrushes to climate change. Global Change Biology, 13: 275–287. doi: 10.1111/j.1365-2486.2006.01290.x
- Issue published online: 27 OCT 2006
- Article first published online: 27 OCT 2006
- Received 2 March 2006; revised version received 16 August 2006 and accepted 1 September 2006
- climate change;
- migration behaviour;
- plastic response;
- Turdus iliacus;
- Turdus merula
Migration is a widespread strategy that enables animals to escape harsh winter conditions. It has been well documented that migration phenology in birds is changing in response to recent climate warming in the northern hemisphere. Despite the existence of large temporal and geographical scale ringing data on birds in Europe, changes in migration strategies in relation to climate warming have not been well studied, mainly because of a lack of appropriate statistical methods. In this paper, we develop a method that enables us to investigate temporal changes in migration strategies from recoveries of dead ringed birds. We estimated migration probability as the ratio between recovery probabilities of conspecific birds originating from different countries but potentially wintering in the same country. We applied this method to two European thrushes: the entirely migrant redwing Turdus iliacus, and the partially migrant blackbird T. merula. We tested for an immediate and a 1-year lagged relationship between our migration probability and climatic covariates (i.e. mean winter temperature in France and the North Atlantic Oscillation). Using ringing-recovery data collected in Finland, Germany, Switzerland and France from 1970 to 1999, we detected contrasting responses in these two species, likely related to their different migratory behaviours. Both species showed a decline in the probability for northern and eastern birds to winter in France. The entirely migratory redwing exhibited a year-to-year plastic response to climate, whereas the decline in the partially migrant blackbird was smooth, suggesting underlying genetic processes. The proposed method, thus, allows us to identify useful indicators of climatic impacts on migration strategies, as well as highlighting differences between closely related species.