Spring Is Early, and So Are the Birds, NPR webcast

This is short real life example of the scientific method. Spring is coming earlier to Europe, thanks to global warming. Scientists figured migrating birds in southern Europe would be able to adjust to the change and leave early (because the early warming would also be obvious where they wintered). But the scientists expected that birds from Africa would not be able to tell that they should leave early.

However, they studied what actual took place and found that the migrating birds from Africa were actually arriving early while those in southern Europe were not. So now they are revising their theories and will do more study to try and determine what is happening and why (for example, how are the birds in Africa deciding to leave early?).