Respect for Wildlife
The following has nothing to do with actually taking a picture, but it does have something to do with how we go about taking wildlife shots. I think that a big part of what helps me to get shot opportunities is that I try to know my subjects. I know where they are likely to be, when they are likely to be active, etc. Especially, though, I know what their "comfort zone" is with people, and I try not to invade that comfort zone.
I see too many people whose "strategy" seems to be to keep getting closer to a bird/animal until they scare the bird or animal away. Frankly, that does neither the bird/animal nor the photographer any good. If animals have "bad" experiences in a particular place, they are not going to keep coming there. Trying to approach nesting birds can drive them off the nest. Even if they come back later, keeping them from the nest at critical times can endanger the well-being of the eggs. Birds, like eagles in the winter, have to conserve their energy. They need that energy to catch fish and to survive. Especially on the coldest days, they don't have energy to waste on fleeing from people who are "stalking them". When we try to approach too closely, not only do we endanger the subjects, but it does us no good, either. At best, it may yield a picture of a bird or animal’s rear end, because, if we are scaring them away, certainly, they are not going to flee flying or running toward us.
Thus, this is a case where, what is good for the species is also best for the photographer. Again, I really do try to respect their comfort zone. When I do so, they stay around. They behave as they normally would, and I get great photo opportunities that I would not get if I tried to move too close and cause stress for them.