Guide to Significant Wildlife Habitat - Door County Web Map

Spider Island
Spider Island is a low, rocky 23-acre island located approximately 0.4 miles from the southern
shore of Newport State Park in Lake Michigan (Judziewicz and Kopitzke 1999). The U.S. Fish and
Wildlife Service owns and manages Spider Island as part of the Green Bay National Wildlife Refuge.
• Spider Island is in the Town of Liberty Grove.
• Soils are nearly level to sloping on old glacial lake beach ridges. Dolostone bedrock is at a depth of
40 or more inches (USDA SCS 1978).
• Vegetation was first documented in 1905 by the Milwaukee Public Museum botanists. A white cedar,
tamarack, and white birch forest dominated the island at that time. Boreal forest and Great Lakes
shoreline understory species were blueflag iris (Iris virginica), wood lily (Lilium philadelphicum),
and Indian paintbrush.
• By 1966, waterbirds like the herring gull had invaded the island degrading the forest to white birch,
white cedar, white spruce, and Canada yew. Shrub species included red-osier dogwood, red
raspberry, and red-berried elder.
• No surface water resources are present on the island.
• In 1983, Gary Fewless, botanist from University of Wisconsin Green Bay, reported exotic herbs and
remnant shrubs like yew and wild black currant dominated the island. The U.S. Fish and Wildlife
Service now reports that the forest has completely disappeared (Judziewicz and Kopitzke 1999).
• Due to the lack of vegetation, wildlife populations on Spider Island are limited. During the nesting
season, the island is home to large breeding colonies of Herring Gulls and Double-crested
Cormorants. Canada Geese and Red-breasted Mergansers are also known to breed on the island.
• No rare plant or animal species have been recorded on the island.
Gravel Island
Gravel Island is 1.7 acres located off the eastern tip of the Door Peninsula (Judziewicz and
Kopitzke, 1999).
• The island is owned and managed by the U.S. Fish & Wildlife Service as Gravel Island NWR. Land
use is maintained as a natural area for wildlife.
• Soils are nearly level to sloping on old glacial lake beach ridges. Dolostone bedrock is at a depth of
40 or more inches (USDA SCS 1978).
• No surface water resources are present on the island.
• Vegetation was surveyed in July of 1999. No vascular plants were observed (Judziewicz and
Kopitzke 1999). There are no known rare plant or animal species.
• The only wildlife species documented from the island are nesting herring gulls.
Grand Traverse Islands 141