The best-selling series of National Audubon Society field guide books have gone mobile, putting information about the natural world at the fingertips of Apple?s iPhone and iPod touch users. The first ...

We account for changes in effort by looking at an effort-weighted measure called “birds per party hour,” which divides the number of each species ... on Maine Audubon’s website ...

The 125-year-old international tradition helps create an annual bird census for research and conservation efforts.