Meet your new hero! My friend Staci, or Spezzy as she's known around the Nerd Fitness community, has one of the best transformations I've ever seen: Working a sedentary desk job, Staci slowly packed on weight and ate like a typical unhealthy American. She also smoked a pack of cigarettes a day.

Read: What the crow knows The new study is silent on the causes of these declines-that's what Rosenberg's team will look at next. But it's widely accepted that "habitat loss and degradation are the largest forces behind the decline of birds," Rosenberg says.