Climate of Our Future

http://www.sciencedaily.com/releases/2010/01/100128130221.htm

ScienceDaily
(Jan. 29, 2010) — Migrating birds can and do keep their travel dates flexible, a new study published online on January 28th in Current Biology, a Cell Press publication, reveals. But in the case of pied flycatchers, at least, an earlier takeoff hasn’t necessarily translated into an earlier arrival at their destination. It appears the problem is travel delays the birds are experiencing as a result of harsh weather conditions on the final leg of their journey through Europe.

The discovery may in a sense be good news as far as birds’ potential to cope under climate change, but it also highlights the vulnerability of long-distance migrants to environmental conditions in general.

“We have been claiming for a while that migratory birds have difficulties in adapting to climate change because of their rigid and rather inflexible timing of spring migration; in Africa and South America, they cannot know when spring starts at their northern breeding grounds,” said Christiaan Both of the University of Groningen in The Netherlands. “This study shows that timing of spring migration is flexible and that birds do respond to climate change, although in a rather indirect way: breeding dates have become progressively earlier, and birds are thus born earlier in the spring. We now show that the effect of early birth is also that the birds migrate early, and migration time has advanced over the last 25 years. The reason that the birds did not advance their arrival is thus not due to a failure to start migration earlier, but because circumstances at passage in Southern Europe have not improved.” Keep Reading