A Maternity Roost of the Endangered Indiana Bat (Myotis sodalis) in an Unshaded, Hollow, Sycamore Tree (Platanus occidentialis)

On 8 July 1992, we discovered a maternity colony of the endangered Indiana bat (Myotis sodalis) in a hollow sycamore tree (Platanus occidentalis), in a totally unshaded pasture, in central Illinois. Bats continually occupied the tree from 8 July until 14 October. Up to 95 bats were present, making this one of the largest summer colonies of Indiana bats ever found. This also is the first published report of a major maternity colony selecting a roost site in a sycamore, in a tree hollow, and in an unshaded location despite a warm summer climate.