Answers to Countdown Challenge Questions
Part III: Questions #17 to #20
Baby birds grow VERY fast. They grew a bit of extra skin from the start so that when they hatch and start eating and start growing, they won't burst out!! They grow into their skin.
The beaks are a little longer, and the tip is no longer yellow.
A wide beak helps a mother hummingbird aim more easily when she's feeding her babies. From the day they hatch, their beaks must be wide enough to hold her open beak, or they're not going to get any food! The beak's bright color helps Mom's aim, too.
The nest is designed to stretch!! As the babies grow, the thick walls and bottom of the nest will stretch, getting thinner but bigger. This happens at just the right time, because the babies don't need as much insulation as their feathers grow in.