I recall a nature photography class where the instructor (a professional photographer) said, when photographing birds, the key is to get a good shot of the eye and to be sure that the eye is at a junction of two grid lines. He said that this would give the most impact and that if that junction wasn’t set exactly in the photo, a post-processing crop could be done to make that happen.
I was fortunate that this pelican rested perfectly still on the pier railing, so that I could get close enough to set up the shot.
Radically Retired 