Among the most welcome features of spring is the renewal of bird song. Can you imagine a spring without the voices of birds? The silence would -- as they say -- be deafening, the absence of their songs like the loss of one of our primary senses. Rachel Carson's 1962 book, Silent Spring, helped found the modern environmental movement. When you hear the birds (like this Spotted Towhee or its cousin, the Eastern Towhee) sing this spring, remember Rachel Carson, and be grateful. You can learn more at RachelCarson.org.