The West Loch and Middle Loch of Pearl Harbor are sites of small urban refuge units. This wetland refuge is primarily devoted to the recovery of Hawaii's four endemic waterbirds (Hawaiian stilt, Hawaiian moorhen, Hawaiian coot, and Hawaiian duck). All four birds are listed as endangered species due to their precipitous decline in the 20th century. The 36-acre refuge unit at West Loch, known as Honouliuli (meaning "dark bay") will host a visitor viewing platform to enable the public to learn more about wildlife, Pearl Harbor, and the history of the refuge.