Mussels are found in large quantities along the Dutch coastline. People collect the mussels from natural beds or farm them for consumption on mussel lots in the Wadden Sea and delta region. In addition to people, shorebirds such as herring gulls and eider ducks also like to eat mussels. Mussels attach themselves to stones or shells with the help of strong threads, known as the mussel's 'beard'. For man and animal alike, it can be quite a job loosening a mussel from a stone. The threads keep the mussel in place so that it isn't affected by movement in the water.