Most bats in temperate climates have a survival strategy in which part of their time is spent foraging for food and water, while the rest is spent roosting. Some species are suffering population declines because urban development destroys habitats. Conservation organizations need to prioritize areas for habitat protection in areas with high development pressure. A Forest Service scientist has developed a modeling framework that helps planners select appropriate habitat reserves. The model helps conservationists to select land with the desired habitat features and size at minimum cost. The mechanics and flexibility of the modeling framework were demonstrated in a case study of Myotis bat conservation on Lopez Island in the San Juan Archipelago, near Seattle. Lopez Island is heavily forested, and conversion of forest lands to home sites is a serious concern. The model identified the land parcels that can be purchased under a given conservation budget to protect the greatest number of Myotis roost sites and associated water sources and foraging habitat. Further, the model helped quantify the gains, in terms of additional roost sites protected, for incremental increases in the conservation budget.