The largest blue heron nesting area in the state of Indiana, Johnson County’s Millard Sutton/Amos W. Butler Audubon Sanctuary, is now a state-dedicated nature preserve. Over 500 nests have been counted there. Breeding pairs of herons mate for life and lay three to seven eggs in March and April. Great blue herons are one of the largest bird species in the U.S. Development in Indianapolis has pushed the herons farther out of town, making the sanctuary necessary. The Central Indiana Land Trust acquired the land in 2002 with privately raised funds.