What is the size of a loon?

The size of a loon varies depending on the species. The common loon, for example, is typically between 28 and 38 inches long and weighs between 5 and 15 pounds. The red-throated loon is slightly smaller, with an average length of 24 to 32 inches and a weight of 3 to 11 pounds. The yellow-billed loon is the smallest of the three common North American loon species, with an average length of 20 to 28 inches and a weight of 2 to 6 pounds.