Some of the most striking examples of rapid changes in lifehistory traits due to climate change are found in migratory birds, especially in the timing of migration and breeding. The combined effect of the public's fascination for birds, a general interest in the phenomenon of migration, and the long history of systematic recording of arrival and departure of migratory birds have generated a wealth of potentially valuable data that can shed light on how bird-migration patterns are affected by climate change and variability.