Pied-billed Grebe

On 1 September 2020, along the Chehalis Bike Trail just north of Olympia, Erika and I encountered a young Pied-billed Grebe. The bird displayed a bunch of self-maintenance behaviors, including stretching and preening. Grebes are interesting birds because they consume lots of feathers. One hypothesis is that grebes continually molt their flank feathers all winter, providing a constant flow of new feathers. Grebes also do a lot of preening just to keep their feathers water-proof.

Ingested feathers are found internally in two locations. Most are found in the stomach. I always thought that these feathers protect the digestive lining from being punctured. Most fish bones, however, completely dissolve in the stomach. Muller and Storer (2020) suggest that the feathers provide substance to the stomach contents, which grebes use to make pellets that they “spit” up. The pellets keep parasites from building up in the upper digestive tract. Feathers are also found at entrance to the small intestine, where they keep hard pieces of prey from entering the intestines.