Northern Spotted Owl populations have declined over the last century, and the subspecies has been listed by the federal government as "threatened" since 1990. The status of the northern Spotted Owl has not been well documented in the North Cascades of Washington and southwestern British Columbia. In 1993, National Park Service (NPS) resource management staff initiated the first comprehensive inventory of Spotted Owls in suitable habitat within North Cascades National Park Service Complex (NOCA), a four-year survey that identified 11 active Spotted Owl territories in NOCA.