They shed all their feathers during an annual molt, which the New Zealand penguin had been doing when found.

NPR: Penguin Found Stranded On New Zealand Beach Dies

This particular male has reached his final molt, clear to me because he now has wings to help him get to where the girls are.

FORBES: Books And Mantids

When I found her this morning, she was mid-molt, her old skin split across her back and her new body wiggling slowly out of it.

FORBES: Books And Mantids

So now, I spend a large portions of my free time watching praying mantids molt, hummingbirds catch gnats over the compost pile, monarch caterpillars munch away the milkweed.

FORBES: Books And Mantids