According to a recent study in Global Change Biology, a journal focused on environmental change, the use and prevalence of hummingbird feeders like those red and clear plastic ones filled with homemade sugar water - changed the size and shape of the birds' beaks in just a few generations. "Very simplified, the bills get longer and they become more slender, and that helps to have a larger tongue inside that can get more nectar from the feeder at a time," one of the biggest takeaways was just how quickly evolution -- something generally assumed to happen over millions of years can take place. "It's a demonstration of how evolution happens, like, literally in front of our eyes. And we just need to pay attention to it," he says.