The eider will eat mussels by swallowing them whole; the shells are then crushed in their gizzard and excreted. ... A particularly famous colony of eiders lives on the Farne Islands in Northumberland, England.

How do eiders Digest mussel shells?

The birds like to snack on mussels, which they swallow whole. The shells are crushed in their gizzard and excreted in small pieces.

How do ducks eat mussels?

A favorite food for diving ducks is mussels, those two to three inch long, dark, oblong shellfish. They dive to the bottom, and rip the mussel, shell and all, from the colony. ... A lot of food is protected by a hard outer shell. Plants and animals have developed defenses against those things which would eat them.