I voted mixture because my process of shooting a subject is as follows:
1) Find a new subject to shoot and get a sharp, unobstructed shot of the subject (e.g: Heron on a branch).
2) Try to take interesting portraits and environmental shots of the subject. (E.g: Heron with reflection in water and a dark backgroun).
3) Observe/learn it's habbits until I know what interesting action shots I could take.
4) Try and take those action shots. (E.g: Heron catching food).
5) Come up with some specific interesting action shots.(e.g: Heron flipping a frog mid-air while a blue sky is reflected in water, using some branches/leaves to form a frame around the bird).
6) Only shoot that specific subject when I can create an interesting image... I don't need another image of a heron on a stick, butvan image of a heron on a stick with multiple other herons in the background, ideally as it takes off... yes.
Now this process can take 30 mins or it can take years, depending on how friendly the subjects are.