Why birds sing at dawn; Yellowstone flooding affects drinking water

You may have noticed a lot of birds chirping outside your window before the sun rises at this time of year. Cornell University ornithology professor Michael Webster talks about the different theories as to why. And, flooding from heavy rain and snow melt forced the evacuation of 10,000 people from Yellowstone National Park. The drinking water in communities like Billings has been affected. Yellowstone Public Radio reporter Olivia Weitz joins us.