Gunnison Island is located in the northwest quadrant of the Great Salt Lake in the U.S. State of Utah (), approximately 55 miles northwest from Salt Lake City and about 6 miles east from the lake's western shore. Approximately 1 mile long and a half-mile wide, Gunnison Island is best known as an important rookery for the American White Pelican (Pelecanus erythrorhynchus). The California Gull (Larus californicus) also nests on the island, and occasional nesters include the Great Blue Heron (Ardea herodias), Common Raven (Corvus corax), Prairie Falcon (Falco mexicanus), and Rock Wren (Salpinctes obsoltetus).[1]
The entire island is the Gunnison Island State Wildlife Management Area.[2] Access to the island is restricted to prevent curious tourists from disturbing the nesting birds.[3]
It is estimated that the population on Gunnison Island (about 10,000) constitutes about 10-20% of the entire American White Pelican population; there are also about 15,000 California gulls that nest on the island.[4][5]
The island's remote location protects it from predators, making it an ideal spot for birds that nest on the ground. Unlike some of the islands in the Great Salt Lake, Gunnison Island does not become a peninsula when the lake level is at its lowest point.
The remoteness also forces the pelicans to travel thirty miles or more to find fresh water and food. The pelicans typically fly east to the Bear River Bird refuge, where the Bear River flows into the Great Salt Lake. In the bird refuge, the water's salinity is low enough that fish can live there. (The Great Salt Lake contains no fish.)
The pelicans have also been known to fly south to Utah Lake, about 100 miles (160 km) away. To get to their destinations, large flocks of adult pelicans ride thermals to a great height, then coast down to their destination.
Gunnison Island was named after John W. Gunnison, an American explorer and surveyor of the Great Salt Lake valley in 1849.
In the mid-1890s, a few enterprising individuals decided to harvest and sell the abundant guano that the nesting birds left behind as fertilizer. The mining activity caused the pelicans to temporarily abandon Gunnison Island as a nesting site, though the gulls remained despite the human company.
Because of the difficulty of obtaining the guano, however, and its tendency to dissolve in the rain and wash back into the Great Salt Lake, the guano industry was abandoned about ten years after it began.[6]