Warmer global temperatures aren't just wiping out the habitat of polar bears and penguins. They're also affecting many species closer to home -- including some right in your back yard. In this year's State of the Birds report, issued earlier this month, researchers from the National Audubon Society, U.S. Department of Interior, Cornell Lab or Ornithology, and others studied how climate change is affecting the habitats, ranges, and populations of birds across North America. OnEarth takes a look at eight vulnerable bird species from across the continent.