This video says about itself:
Cahow Chick‘s Juvenile Plumage Starting to Show – May 2, 2018
The afternoon following a parental feeding visit in the burrow, the well-fed Cahow chick is beginning to show obvious signs of juvenile plumage development. Get a glimpse at how well the chick’s head feathers have developed around its bill in this clip when it scratches an itch and sloughs away down in front of the camera.
The CahowCam is a collaboration between the Cornell Lab of Ornithology and the Nonsuch Expeditions. You can watch the cam live at http://allaboutbirds.org/cahows and learn more about Nonsuch Island‘s environs (including the cahow) at http://nonsuchisland.com.