Gunnison Island
Encyclopedia
Gunnison Island is located in the northwest quadrant of the Great Salt Lake
in the U.S. State
of Utah
(41.339°N 112.858°W), 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).
The entire island is the Gunnison Island State Wildlife Management Area. Access to the island is restricted to prevent curious tourists from disturbing the nesting birds.
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.
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 (160.9 km) away. To get to their destinations, large flocks of adult pelicans ride thermal
s to a great height, then coast down to their destination.
, 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.
Great Salt Lake
The Great Salt Lake, located in the northern part of the U.S. state of Utah, is the largest salt water lake in the western hemisphere, the fourth-largest terminal lake in the world. In an average year the lake covers an area of around , but the lake's size fluctuates substantially due to its...
in the U.S. State
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...
of Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
(41.339°N 112.858°W), 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
American White Pelican
The American White Pelican is a large aquatic bird from the order Pelecaniformes. It breeds in interior North America, moving south and to the coasts, as far as Central America, in winter....
(Pelecanus erythrorhynchus). The California Gull
California Gull
The California Gull Larus californicus is a medium-sized gull, smaller on average than the Herring Gull but larger on average than the Ring-billed Gull, though may overlap in size greatly with both....
(Larus californicus) also nests on the island, and occasional nesters include the Great Blue Heron
Great Blue Heron
The Great Blue Heron is a large wading bird in the heron family Ardeidae, common near the shores of open water and in wetlands over most of North and Central America as well as the West Indies and the Galápagos Islands. It is a rare vagrant to Europe, with records from Spain, the Azores and England...
(Ardea herodias), Common Raven
Common Raven
The Common Raven , also known as the Northern Raven, is a large, all-black passerine bird. Found across the northern hemisphere, it is the most widely distributed of all corvids...
(Corvus corax), Prairie Falcon
Prairie Falcon
The Prairie Falcon is a medium-sized falcon of western North America.It is about the size of a Peregrine Falcon or a crow, with an average length of 40 cm , wingspan of 1 metre , and weight of 720 g...
(Falco mexicanus), and Rock Wren
Rock Wren
The Rock Wren is a small songbird of the wren family. It is the only species in the genus Salpinctes.The 12 cm long adults have grey-brown upperparts with small black and white spots and pale grey underparts with a light brown rump...
(Salpinctes obsoltetus).
The entire island is the Gunnison Island State Wildlife Management Area. Access to the island is restricted to prevent curious tourists from disturbing the nesting birds.
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.
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
Utah Lake
Utah Lake is a freshwater lake in the U.S. state of Utah. On the western side of Utah Valley, the lake is overlooked by Mount Timpanogos and Mount Nebo. The lake's only river outlet, the Jordan River, is a tributary of the Great Salt Lake and is highly regulated with pumps. Evaporation accounts...
, about 100 miles (160.9 km) away. To get to their destinations, large flocks of adult pelicans ride thermal
Thermal
A thermal column is a column of rising air in the lower altitudes of the Earth's atmosphere. Thermals are created by the uneven heating of the Earth's surface from solar radiation, and are an example of convection. The sun warms the ground, which in turn warms the air directly above it...
s to a great height, then coast down to their destination.
History
Gunnison Island was named after John W. GunnisonJohn W. Gunnison
John Williams Gunnison was an American military officer and explorer.-Biography:Gunnison was born in Goshen, New Hampshire in 1812. He graduated from West Point in 1837, second in his class of fifty cadets. His military career began in Florida, where he spent a year in the campaign against the...
, an American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
explorer and surveyor of the Great Salt Lake
Great Salt Lake
The Great Salt Lake, located in the northern part of the U.S. state of Utah, is the largest salt water lake in the western hemisphere, the fourth-largest terminal lake in the world. In an average year the lake covers an area of around , but the lake's size fluctuates substantially due to its...
valley in 1849.
In the mid-1890s, a few enterprising individuals decided to harvest and sell the abundant guano
Guano
Guano is the excrement of seabirds, cave dwelling bats, and seals. Guano manure is an effective fertilizer due to its high levels of phosphorus and nitrogen and also its lack of odor. It was an important source of nitrates for gunpowder...
that the nesting birds left behind as fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
. 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.