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Contact information
For information on State Natural Areas, contact:
Thomas Meyer
Natural areas conservation biologist

Wisconsin State Natural Areas Program Sister Islands (No. 47)

Sister Islands

Photo by E. Epstein



Door County. T32N-R28E, Section 30. 6 acres.



Sister Islands is an historic gull and tern nesting area consisting of two low, gravel islands. It is one of the important gulleries in Green Bay. High water levels in the early 1980's have greatly reduced the size of the islands'; in fact, during the low water levels of the 1960's, the islands were connected. The most common breeding birds are herring gulls, but small numbers of red-winged blackbird, common tern, pintail, and mallard are also present. The flora is quite variable due to the disturbance caused by nesting birds and fluctuating water levels. During low water years, shrubs and weeds dominate with small numbers of boxelder, red-osier dogwood, elderberry, bitter nightshade, spotted jewelweed, and stinging nettle also grow here. Sister Islands is owned by the DNR and was designated a State Natural Area in 1966.


Driving directions

By boat 2 miles northwest of the public launch in Sister Bay.


Sister Islands is owned by:

  • WDNR


Site objectives

Manage the site for bird nesting habitat. Natural processes will determine the structure of the natural communities of this site. Provide opportunities for research and education on gull and tern nesting islands.

Management approach

Natural fluctuations in lake levels and guano deposition keep the island nearly tree free. Allowable activities during nesting season are limited to bona fide research access with federal permits in-hand. Recreational landings are permitted when the birds are not present.

Last revised: Friday, December 15, 2017