This limestone island is an important part of the eastern Lake Ontario flyway, a biannual landing site for migratory birds. . Naturalists speculate that the island was part of a route for plant migration across the eastern end of Lake Ontario following the retreat of the glaciers. Several southern species of plants, rare in eastern Ontario, are found here. Meadows, shrub thickets, and oak-hickory forests also grow on Timber Island. Access is by boat only and requires permission from the Superintendent who is located at Sandbanks Provincial Park. The island, which features a low bluff around the shore, is without docking or other visitor facilities.