The common guillemot is a marine bird that inhabits the rocky cliffs of the northern hemisphere. Depending on the region, it may also be referred to as the common murre, thin-billed murre, or the Brunnich's guillemot. These birds are known for their distinctive appearance, with a black back and white underbelly. They have a sharp beak that is perfect for catching small fish and crustaceans. Although they are called "common," they are an important species in their ecosystem and are beloved by bird watchers and nature enthusiasts alike. When searching for information on these birds, it's important to be aware of the various synonyms used in different regions.