Gravel Island National Wildlife Refuge
Encyclopedia
Gravel Island National Wildlife Refuge is a National Wildlife Refuge
located off the Door Peninsula
in Wisconsin
. Founded in 1913 the refuge consists of two Lake Michigan
islands, that act as nesting grounds for native bird species. The refuge is part of the Wisconsin Islands Wilderness Area, and as such it is off-limits to the public to preserve the habitat of the islands. It is inhabited by large colonies of shore birds, waterfowl
and also home to a pair of Great Black-backed Gulls, one of farthest westward breeding sites of the species.
visited the area numerous times to study the Herring Gull
populations. In 1906 and 1907 while visiting Gravel Island, he noted very large colonies of Herring Gulls as well as Caspian Tern
s, observed their behavior and collected specimens from the island. In 1913, under executive order the refuge was formed from Gravel Island and Spider Island to protect the breeding grounds of birds living there. Upon its formation it became the 29th refuge in the U.S and third in the great lakes region. In 1970 the refuge became part of the Wisconsin Islands Wilderness Area, one of the smallest in the country. Many studies have been performed at the refuge since the 1970s, and in recent times efforts have focused on migrating habits, breeding and tagging of the birds.
In 2009 the refuge became part of a Comprehensive Conservation Planning (CCP) program which will help manage the refuge more efficiently. The plan will allow for long-term continuity in refuge management, make sure that the refuge is consistent with the policies of the National Wildlife Refuge System and improve budgets for the refuge.
in Lake Michigan
near Porte des Morts
or "Death's Door", and is in a geographically rugged part of the Niagara Escarpment
. The islands are made of mainly limestone, with little to no vegetation growing on them. They were shaped by years of receding water, powerful pre-glacial rivers, and advancing glaciers. As a result the islands are mainly flat and stick up only a few meters above the lake.
or a place of shelter. The Great Black-backed Gull
(Larus marinus) is known to have a small breeding colony on Gravel Island, and historically on Spider Island. In 1994 the species was discovered on Spider Island, making it the westernmost breeding on record at the time. Large colonies of Herring Gulls
(Larus smithsonianus) and Double-crested Cormorant
s (Phalacrocorax auritus) are found on both islands, while a colony of Caspian Tern
s (Sterna caspia) can be found on Gravel Island. Scattered populations of waterfowl
nest on Spider Island; these include the Canada Goose
(Branta canadensis), American Black Duck
(Anas rubripes) and Mallard
(Anas platyrhynchos).
National Wildlife Refuge
National Wildlife Refuge is a designation for certain protected areas of the United States managed by the United States Fish and Wildlife Service. The National Wildlife Refuge System is the world's premiere system of public lands and waters set aside to conserve America's fish, wildlife and plants...
located off the Door Peninsula
Door Peninsula
The Door Peninsula is a peninsula in eastern Wisconsin, separating the southern part of the Green Bay from Lake Michigan. The peninsula begins in northern Brown and Kewaunee counties and proceeds northeast to include all of Door County. It is the western portion of the Niagara Escarpment. Well...
in Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
. Founded in 1913 the refuge consists of two Lake Michigan
Lake Michigan
Lake Michigan is one of the five Great Lakes of North America and the only one located entirely within the United States. It is the second largest of the Great Lakes by volume and the third largest by surface area, after Lake Superior and Lake Huron...
islands, that act as nesting grounds for native bird species. The refuge is part of the Wisconsin Islands Wilderness Area, and as such it is off-limits to the public to preserve the habitat of the islands. It is inhabited by large colonies of shore birds, waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
and also home to a pair of Great Black-backed Gulls, one of farthest westward breeding sites of the species.
History
In the years before the refuge's founding, multiple expeditions were made to the Islands. One Ornithologist named Henry L. Ward, then-curator of the Milwaukee Public MuseumMilwaukee Public Museum
The Milwaukee Public Museum is a natural and human history museum located in downtown Milwaukee, Wisconsin, USA. The museum was chartered in 1882 and opened to the public in 1884; it is a not-for-profit organization operated by the Milwaukee Public Museum, Inc. MPM has three floors of exhibits...
visited the area numerous times to study the Herring Gull
American Herring Gull
The American Herring Gull or Smithsonian Gull is a large gull which breeds in North America. It is often treated as a subspecies of the European Herring Gull but is now regarded as a separate species by some authorities.Adults are white with gray back and wings, black wingtips with white spots,...
populations. In 1906 and 1907 while visiting Gravel Island, he noted very large colonies of Herring Gulls as well as Caspian Tern
Caspian Tern
The Caspian Tern is a species of tern, with a subcosmopolitan but scattered distribution. Despite its extensive range, it is monotypic of its genus, and has no subspecies accepted either...
s, observed their behavior and collected specimens from the island. In 1913, under executive order the refuge was formed from Gravel Island and Spider Island to protect the breeding grounds of birds living there. Upon its formation it became the 29th refuge in the U.S and third in the great lakes region. In 1970 the refuge became part of the Wisconsin Islands Wilderness Area, one of the smallest in the country. Many studies have been performed at the refuge since the 1970s, and in recent times efforts have focused on migrating habits, breeding and tagging of the birds.
In 2009 the refuge became part of a Comprehensive Conservation Planning (CCP) program which will help manage the refuge more efficiently. The plan will allow for long-term continuity in refuge management, make sure that the refuge is consistent with the policies of the National Wildlife Refuge System and improve budgets for the refuge.
Geography and geology
The refuge covers 28 acre (11.3 ha) which comes from two islands, Spider Island spanning 23 acres (9.3 ha) and Gravel Island at a size of 4 acres (1.6 ha). The refuge is located off the east side of the Door PeninsulaDoor Peninsula
The Door Peninsula is a peninsula in eastern Wisconsin, separating the southern part of the Green Bay from Lake Michigan. The peninsula begins in northern Brown and Kewaunee counties and proceeds northeast to include all of Door County. It is the western portion of the Niagara Escarpment. Well...
in Lake Michigan
Lake Michigan
Lake Michigan is one of the five Great Lakes of North America and the only one located entirely within the United States. It is the second largest of the Great Lakes by volume and the third largest by surface area, after Lake Superior and Lake Huron...
near Porte des Morts
Porte des Morts
Porte des Morts, also known as Porte des Mortes, the Door of Death, and Death's Door is a strait linking Lake Michigan and Green Bay between the northern tip of the peninsula of Door County, Wisconsin and a group of islands historically known as the Potawatomi Islands and dominated by Washington...
or "Death's Door", and is in a geographically rugged part of the Niagara Escarpment
Niagara Escarpment
The Niagara Escarpment is a long escarpment, or cuesta, in the United States and Canada that runs westward from New York State, through Ontario, Michigan, Wisconsin and Illinois...
. The islands are made of mainly limestone, with little to no vegetation growing on them. They were shaped by years of receding water, powerful pre-glacial rivers, and advancing glaciers. As a result the islands are mainly flat and stick up only a few meters above the lake.
Flora
Spider island had a birch-cedar-tamarack forest until the late 1970s, but succumbed to the thousands of birds living on the island. The trees of Spider island have now fallen over or been washed away and no permanent vegetation is known on Gravel island.Fauna
The refuge is home for to a wide array of bird species that either use the islands as nesting groundsBird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
or a place of shelter. The Great Black-backed Gull
Great Black-backed Gull
The Great Black-backed Gull is the largest gull in the world, which breeds on the European and North American coasts and islands of the North Atlantic...
(Larus marinus) is known to have a small breeding colony on Gravel Island, and historically on Spider Island. In 1994 the species was discovered on Spider Island, making it the westernmost breeding on record at the time. Large colonies of Herring Gulls
American Herring Gull
The American Herring Gull or Smithsonian Gull is a large gull which breeds in North America. It is often treated as a subspecies of the European Herring Gull but is now regarded as a separate species by some authorities.Adults are white with gray back and wings, black wingtips with white spots,...
(Larus smithsonianus) and Double-crested Cormorant
Double-crested Cormorant
The Double-crested Cormorant is a member of the cormorant family of seabirds. It occurs along inland waterways as well as in coastal areas, and is widely distributed across North America, from the Aleutian Islands in Alaska down to Florida and Mexico...
s (Phalacrocorax auritus) are found on both islands, while a colony of Caspian Tern
Caspian Tern
The Caspian Tern is a species of tern, with a subcosmopolitan but scattered distribution. Despite its extensive range, it is monotypic of its genus, and has no subspecies accepted either...
s (Sterna caspia) can be found on Gravel Island. Scattered populations of waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
nest on Spider Island; these include the Canada Goose
Canada Goose
The Canada Goose is a wild goose belonging to the genus Branta, which is native to arctic and temperate regions of North America, having a black head and neck, white patches on the face, and a brownish-gray body....
(Branta canadensis), American Black Duck
American Black Duck
The American Black Duck is a large dabbling duck. American Black Ducks are similar to Mallards in size, and resemble the female Mallard in coloration, although the Black Duck's plumage is darker...
(Anas rubripes) and Mallard
Mallard
The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....
(Anas platyrhynchos).