The Butte Creek Ecological Preserve and Butte Creek Canyon Ecological Reserve consist of 2 distinct management units, the Preserve, aka the "Honey Run Unit" owned and managed by the Chico State Research Foundation, and the "Virgin Valley" and "Canyon" Units , owned and managed by the California Department of Fish and Wildlife. The units are located east of Chico along Butte Creek in northern California. This stretch of Butte Creek is spawning habitat for the largest population of Central Valley spring-run Chinook salmon, an evolutionarily significant unit that is listed as threatened under the Endangered Species Act. Fall-run Chinook salmon and steelhead trout also spawn in the creek. The California Department of Fish and Wildlife considers the Butte Creek Canyon Ecological Reserve valuable in terms of providing wildlife habitat and protection of critical shaded riverine and aquatic resources. The Butte Creek population of Central Valley spring-run Chinook salmon is the largest and one of the few remaining self-sustaining populations in the Central Valley, and is listed as threatened under both the state and federal endangered species acts. The reserves protect habitat for other species such as bald eagle, Swainson's hawk, beaver and the western pond turtle. At the headwaters of Butte Creek is a separate nature reserve called the Butte Creek House Ecological Reserve is managed by the California Department of Fish and Wildlife (CDFW). Reserve units detail Butte Creek Canyon Unit This unit is located two miles (3 km) southeast of the City of Chico and is in size. It is managed by CDFW. This unit has a high amount of non-native grasses (over 40 per cent) and several sensitive or rare plants, including California black walnut (Juglans hindsii) and shield-bracted monkey flower (Mimulus glaucescens). Virgin Valley Unit This unit is in size and is also managed by CDFW. It is one half mile downstream from the Butte Creek canyon mouth on an alluvial apron. This unit contains forests of valley oak (Quercus lobata) growing on streamside terraces and on the alluvial aggregate. Honey Run Unit This unit is managed by Chico State University Research Foundation in cooperation with other agencies and is located within the Butte Creek canyon proper. It is in size. The area of Butte Creek had been used in dredge mining from the 1800s to about 1950, and mining for sand and gravel from the 1950s to the 1970s. In 1980, a cluster development project