There is an island in a fjord in northwestern Iceland where eider ducks nest in substantial numbers. They use their own down to line their nests, and when the chicks leave the nest, a farmer harvests the abandoned down, cleans, packs and ships it to supply much of the world market. The island is shared by a population of nesting Arctic terns. When anyone approaches a nest, the male becomes aggressive, hovering nearby, and may attack if the intruder does not retreat. The Arctic Tern lives on average 20 years, and at nearly 71,000 km per year, has by far the longest migratory route of any species. It its lifetime it will likely fly 2.4 million km!