Hundreds of millions of birds die each year in the United States as a result of collisions with plate-glass. It is estimated to be the largest source of avian mortality associated with humans. As our population continues to grow by an expected three billion individuals, more structures will be built, and the threat will increase. Further, modern buildings are frequently designed with large expanses of glass, often for energy efficiency, which greatly increases their danger to birds. Birds are vital to human well-being. They provide a number of ecosystem services, so their loss is our loss. For example, birds are vital to seed dispersal and plant pollination. They also reduce the numbers of insect pests, saving on crop losses and lessening the need for pesticides. Birds strengthen the resiliency of ecosystems, and are a vital part of our culture—a source of pleasure, inspiration and beauty.