Just read the article. The wing span only decreased one centimeter. That is less than one millimeter a year. A one centimeter difference in wingspan won't help a bird at all, let alone one millimeter. You are not going to be "selected" because of one centimeter. Most of the birds I have hit with my car are usually in the middle of the windshield. To avoid the impact, the bird would have had to suddenly move more than two+ feet out of the way. One centimeter ain't going to help you there either...
I remember the 1980's. Lots of rain, lush green fields. Now here in the south in 2012, Everything is dead and brown, with fires everywhere from drought. Yet these two dimwitted "scientist" blame "evolution" for these smaller birds.
Probably just used the word evolution to get more grant money. Crooks...