While most of us start listing for our own sense of accomplishment (or compulsion!), those notebooks can actually help ornithologists determine where the birds live, whether their populations are thriving, stable, or in decline, and the human and environmental factors affecting them.
At the same time, we birders can benefit from one another’s sightings. Are you looking for a particular species to add to your life list? Did you know that you can find out where others have seen that bird?