Climate change and population declines in a long-distance migratory bird.

The possible ecological effects of climate change are often in the news, as is the matter of whether the potential impact can be predicted. New work on a migratory bird, the pied flycatcher, takes things a stage further by showing how a climate-related population decline was actually caused. Timing is key. Over the past 17 years flycatchers declined strongly in areas where caterpillar numbers (food for the nestlings) peak early, but in areas with a late food peak there was no decline. The young birds arrive too late where caterpillars have responded to early warmth. Mistiming like this is probably a common consequence of climate change, and may be a major factor in the decline of many long-distance migratory bird species.