Cook Island Nature Reserve was reserved to protect the seabirds and shorebirds that roost and breed on the island. The reserve is listed on the Register of the National Estate because of its significance as a breeding habitat for seabirds. Twelve migratory bird species of international significance visit the island, of which two are listed as endangered and two as vulnerable under the Threatened Species Conservation Act 1995. A further three bird species are also listed as vulnerable but are not listed under international treaties.
Cook Island is important to the Bundjalung Aboriginal people and there are a number of mythological stories associated with the island.
