Why Grebes Eat Feathers
Grebes, as a group, are known for eating feathers – usually their own. The obvious question is – why? There would be virtually no nutritional value in a feather. Clark’s Grebe eating a feather I’ve photographed four species of grebes – Western Grebe, Clarks Grebe (these two are very similar), Pied-billed Grebe and Eared Grebe. I’ve been able to document feather eating in all but the Eared Grebe. Western Grebe parent feeding feather to young Over a period of perhaps a half hour I watched this adult feed several feathers to the chicks, who seemed almost as eager to consume the feathers as they did the fish provided by the parents. Western Grebe chick reaching for a feather from its parent Feathers are fed to the young almost immediately after hatching. In fact, feathers are very often the first item eaten by newly hatched chicks of many grebe species. The purpose(s) of feather eating is unproven but evidence suggests that the behavior has these benefits for the birds. Some of the ingested feathers form a plug in the pylorus, between the stomach and small intestine, which acts as a strainer to keep fish bones in the stomach long enough to be completely digested. Most swallowed feathers end up in the stomach lumen, mixed with food. They eventually (along with any indigestible matter) form pellets that are ejected through the mouth. The continuous passage of these pellets through the upper digestive system minimizes the buildup of a variety of parasites that are very common there and plague grebes. Pied-billed…