Navigating our way through Union, Maine to a coastal destination recently, my wife Mary and I looked up at an intersection and were startled to see a sparrow pop out of a street sign. The sign was a gable roofed duplex birdhouse with a hole and perch at each end. Routed into the weathered wooden side and emblazoned in bright yellow was the name of the road. Our surprise grew into delight when we realized that every street in this town of about 2,500 just 35 minutes southeast of Augusta, was indentified in this way. Sometimes the birdhouses were supplemented with standard reflective green signs nearby, but other corners had birdhouses alone. We grew used to seeing finches, sparrows and wrens at road crossings. Straw and other nest materials often hung out of the holes. At quiet junctures, I could hear the vibrant chirping sound of life inside. We spent less than thirty minutes passing through Union, but the bird-box signs made it one of the most memorable moments of a weeklong trip.