ocr: DID YOU KNOW? During the breeding season, puffins grow brightly colored bill sheaths. These outer. layers ofthe bill are made ofl keratin (at type offibrous protein).As part oft the display plumage, puffins also grow a yellow wattle on the base oft the beak and on their eyelids. In late summer the bill sheaths are shedand the wattles shrink, and the beak becomes dull andnarrower.
