On 8/15/22, I added a post on this site about the Pied-Billed Grebe (PBG), including photos and a brief description. Below is one paragraph from the post:
Like other grebes, the PBGs ingest large amounts of their own feathers, even feeding these to young chicks. It would be like us eating our own hair and fingernails. Except that it helps them digest food and they don’t find it repellent. Ornithologists speculate that the matted feathers in their stomach act as a sieve to keep out sharp objects like a crayfish carapace. Periodically the PBGs regurgitate pellets of accumulated feathers and prey by-product.
I found this to be an interesting and strange fact about the grebe. Eating feathers to improve digestion, really? Last week, quite accidentally, I photographed a PBG in the process of regurgitating its stomach pellet. This is something I never expected to witness. I did not even know what I was seeing at the time. You might find the images a little disgusting, but these birds are fine with vomiting in public!
Below is a series of four photos in sequence of a process that took a few seconds. I guess this little grebe will be back to restocking its belly with fresh feathers.