Hummingbirds Day 6: Wrinkled Skin Look closely at the skin on these babies. Q: Why do you think the babies' skin is so wrinkled? (Answer under photo.) A. 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. <Back to Gallery Next> Facebook Pinterest Twitter © 1997 – 2019 Journey North. All rights reserved.