First shot:
As others have said, it's a little busy. The trees aren't clean lines, which help a lot in this type of shot. There's no point of interest, and the lines really don't lead anywhere. It's not a horrible shot, it's just boring without a subject or leading lines for the eye to follow.
Second shot:
Background's distracting, and with living things, almost always give them room to "look" in the direction they're facing, so you need more room in the front of the bird than in the back. I'd have tried to get lower, or waited for a plainer background. It also looks like the feathers are the point of focus instead of the eye, that's generally a bad thing in any picture of something with eyes unless you're looking for a specific effect. It's not a bad shot, it's just not the best shot you might have made.
Third shot:
No leading lines, distracting background and the lighting is a bit wrong for the subject. Adding some fill with a reflector and moving to the front more would help. This is the only one of the three that I can't find any merit in- I can't see what you "saw" in the shot, probably because of a lack of contrast in the center of the shot.
Given the range of subject/styles in these three shots, I'd recommend trying to nail one sort of shooting for say 60-70% of your shots first, it helps to be able to compare a certain type of shot to others like it to gauge progress. Variety is the spice of life, and versatility is good in a photographer, but I think starting out focusing on one sort of thing is massively helpful to gain sight in composition and exposure.