Individual responses in spring arrival date to ecological conditions during winter and migration in a migratory bird
Article first published online: 15 JUN 2009
© 2009 The Authors. Journal compilation © 2009 British Ecological Society
Journal of Animal Ecology
Volume 78, Issue 5, pages 981–989, September 2009
How to Cite
Balbontín, J., Møller, A. P., Hermosell, I. G., Marzal, A., Reviriego, M. and De Lope, F. (2009), Individual responses in spring arrival date to ecological conditions during winter and migration in a migratory bird. Journal of Animal Ecology, 78: 981–989. doi: 10.1111/j.1365-2656.2009.01573.x
- Issue published online: 29 JUL 2009
- Article first published online: 15 JUN 2009
- Received 23 June 2008; accepted 11 May 2009 Handling Editor: Ryan Norris
- barn swallow;
- bird migration;
- climate change;
1. We studied lifetime arrival patterns in the barn swallow (Hirundo rustica L.) in relation to variation in ecological conditions, as reflected by the normalized difference vegetation index (NDVI) in the Sub-Saharan winter quarters and at stopover sites in North Africa.
2. Migratory birds have recently advanced their arrival dates, but the relative role of microevolution and phenotypic plasticity as mechanisms of response to changing environmental conditions remains unknown. To distinguish between these two possibilities, we investigated the change in the arrival date using cross-sectional and longitudinal analyses.
3. We predicted that the effect (i.e. slopes) of environmental conditions in stopover or winter areas on arrival date should be similar using cross-sectional and longitudinal analyses in case phenotypic plasticity is the underlying mechanism, or they should differ in case microevolution is the mechanism.
4. As expected according to a previous cross-sectional study, we found an advance in the arrival date when ecological conditions improve in stopover areas and a delay in the arrival date when ecological conditions improve in the winter quarters.
5. Change in the arrival time at the breeding grounds due to ecological conditions found en route and, in the winter areas, was mainly due to phenotypic plasticity as shown by similarities in the slopes found in these relationships using cross-sectional and longitudinal analyses.
6. We also investigated sex and age of barns swallows as sources of variation in the arrival time with respect to conditions experienced in winter and stopover areas. We found that earlier arrival at the breeding grounds due to prevailing ecological conditions found en route in North Africa was similar for males and females of all age-classes. In contrast, individuals tended to delay departure when ecological conditions improved in the winter quarters, but this delay differed among age classes, with old individuals delaying departure more than middle-aged and yearling birds.
7. The migratory response of individuals to changing climatic conditions experienced during different parts of their life provides evidence for individuals responding differently to prevailing conditions in the winter quarters depending on their age, but not to conditions experienced en route during spring migration.