Evidence for the impact of global warming on the long-term population dynamics of common birds.

Taking the opportunity in 2003 of the exceptionally warm spring in France as a natural simulation of possible future climate, we analysed common bird productivity using the French long-term capture-recapture national monitoring scheme. Two-thirds of the 32 species studied had an above-average productivity in 2003. However, this gain in productivity was not consistent among species, with a relatively low productivity for species exhibiting a long-term decline and relatively high productivity for stable or increasing species. Such links between long-term and short-term dynamics suggest that the impact of increasingly warm springs on productivity is a major component of the recent population dynamics of a variety of common bird species.