Cascade Head Experimental Forest, located on the central Oregon Coast, was established in 1934 to represent typical Sitka spruce-western hemlock forests. The Neskowin Crest Research Natural Area was established in 1941 in the northwest corner of the experimental forest. In 1974, an act of Congress established the Cascade Head Scenic Research Area, which includes the western half of the experimental forest. The designation added several prairie headlands, the Salmon River estuary (the only estuary on Forest Service lands in the conterminous United States), and contiguous private lands to the mature forest ecosystems already part of the experimental forest. The result has been a more diverse and coastal-related research program. Together, the experimental forest and the scenic research area were designated a Biosphere Reserve as part of UNESCO's Man and the Biosphere program in 1980. The ecosystems here are home to more than 350 species of wildlife. There are four federally listed endangered species that use or inhabit the Cascade Head area: spotted owl, marbled murrelet, coho salmon, and Oregon silver spot butterfly. The recently restored Salmon River estuary provides a critical juncture between fresh and salt water, supports numerous forms of life, and maintains staging areas for upstream spawning migrations of anadromous fish and rearing areas for juveniles and smolts.