Roger Tory Peterson was an American naturalist, ornithologist and educator. If you are a birder, you may have one of his field guides. He published his first bird guide in 1934 and it went through 6 editions. He won award for natural science, conservation and ornithology.
In this century, no one has done more to promote an interest in living creatures than Roger Tory Peterson, the inventor of the modern field guide.
~ Paul R. Ehrlich, 1988
Birds are a good environmental indicators because they live in almost every environment and in almost every niche in those environments. Being at the top of the food chain, they are vulnerable to chemicals and, as a species, they have a wide range of diets. Birds are also easy to see, identify and study. Changes in bird populations and health will inevitable affect the biodiversity of an area.
