Happy National Park Week, everyone! That's right, it's that time of year when we set aside a full week to appreciate one of America's greatest treasures. (Don't forget that means free admission to any park this coming weekend!) Of course, to many of us, every day is a good day to celebrate our national park system, which protects some of the most famous landmarks in the world. A few of the names—Yosemite, Grand Canyon, Everglades—even evoke the very essence of what we are as a nation. The system reflects the breadth of the United States: its lands, its people, its history, and its culture. Oh yeah, and national parks are home to a ton of birds. Most people think of our national parks as remote destinations requiring a long trip, but there are national parks close to wherever you live. The national park system is composed of 417 distinct sites, covering all 50 states and most of our island territories. There is great birding to be found in most of them, and...