Book excerpt: Wood thrush, Kentucky warbler, the Eastern kingbird-migratory songbirds are disappearing at a frightening rate. By some estimates, we may already have lost almost half of the songbirds that filled the skies only forty years ago. Renowned biologist Bridget Stutchbury convincingly argues that songbirds truly are the "canaries in the coal mine"-except the coal mine looks a lot like Earth and we are the hapless excavators. Following the birds on their six-thousand-mile migratory journey, Stutchbury leads us on an ecological field trip to explore firsthand the major threats to songbirds: pesticides, still a major concern decades after Rachel Carson first raised the alarm; the destruction of vital habitat, from the boreal forests of Canada to the diminishing continuous forests of the United States to the grasslands of Argentina; coffee plantations, which push birds out of their forest refuges so we can have our morning fix; the bright lights and structures in our cities, which prove a minefield for migrating birds; and global warming. We could well wake up in the near future and hear no songbirds singing. But we won't just be missing their cheery calls, we'll be missing a vital part of our ecosystem. Without songbirds, our forests would face uncontrolled insect infestations, and our trees, flowers, and gardens would lose a crucial element in their reproductive cycle. As Stutchbury shows, saving songbirds means protecting our ecosystem and ultimately ourselves.