This is bird note.

Some birds are just misunderstood and have been for centuries.

Take the eared grebe, for example, the earliest description in the North American literature,

dating from 1577, and based on Aztec observations, notes,

its food is its feathers. Only sometimes it eats fish.

Strange as it sounds, grebes do indeed eat their own feathers. Eard grebes eat mainly brine shrimp

and aquatic insects, which have rigid exoskeletons, making them both tough to digest and potentially

damaging to the intestines. So, grebes evolve to use their feathers as a way to slow down digestion.

After the bird swallows them, the feathers enter a three-part stomach, first a storage chamber,

then a gizzard, and lastly, a pouch. The feathers form dense balls in both the gizzard and final pouch, and appear to slow the passage of food long enough that the food can be safely liquefied.

The tough bits are then regurgitated within a ball of feathers, much the way owls spit up pellets of bones from their prey.

A greed may pop out as many as six feather balls in an evening.

For Bird Note, I'm Michael Stein.