Use these easy tips to transform a typical yard into a bustling habitat for birds. "Location! Location! Location!" We considered this old real-estate adage carefully when shopping for our first home two decades ago. But three additional factors -- food, water and shelter -- now figure into our property purchases. Although it may seem strange to real estate agents, we evaluate potential residences not only for human requirements but also for those of our wild neighbors. Two years ago, we moved into asuburban development at the foot of the Blue Ridge Mountains in central Maryland. It's a classic neighborhood of single-family homes built on half- to one-acre lots. Most of the homes are 15 to 30 years old, with well-established landscaping and maturing trees.