I have a buddy who is a biology instructor. He has a field book(s) with entries for almost all his hikes, hunts, fishing expeditions, etc. for the last 20 years or so. I am not sure what percentage, but it seems a lot and on several occasions questions have come up and he has been able to refer back to his field book. Drawings, maps, phrenology notes, quotes, and everything else. Some done in the field and some done that night. I have seen a few entries related to questions I have and was impressed. All of them together must contain an astonishing amount of information.
No, I haven't been smart enough to copy his behavior. I can't draw nearly so well nor do I have the diverse knowledge of nature he does.