Less than Bird Brained?

There was a report yesterday on National Public Radio’s All Things Considered about a study of migratory Arctic birds. It seems that with earlier spring times the birds are migrating north earlier. This is a case of the early birds catching the worm, or rather the flies and mosquitoes that hatch earlier than they used to. Now, this is puzzling, How do the birds know that spring will arrive earlier? I am fairly certain that they are not wired up to weather.com, and contrary to what some would say I do not thing the Intelligent Designer is whispering in their ear. (Sort of the inverse of “a little birdie told me”. The best explanation is that in the relatively short time that the climate has been warming up the birds have evolved through Natural Selection. That is, the few birds that have migrated earlier have gotten the lions share of the insect feast and so have been more successful in raising other early birds. While this is still not the final word it does present a question to me.
If even the birds realize the Earth is warming up, and have changed accordingly, why can’t our politicians here in the US realize it? Perhaps it has something to do with those politicians oil connections? Oh, I am sure I am just being cynical and paranoiac. There can’t be any connection between the two.