I love that first picture! The picture is a little too small for me to be able to tell if the focus is right on, or if it’s slightly back-focused, but great job on:
• catchlight in the eye. Bird looks “alive.”
• unique expression and activity. Bird looks “curious, active.”
• eye-level perspective.
• high focal length, combined with (relatively) low aperture number, resulting in nice background blur.
One thought: it might be nice if the bird had been brighter than the background rather than the reverse. Naturally, the eye of an observer will go to the brightest spots in the picture first. You can’t move the sun (except by waiting,) but you can move yourself, as explained helpfully here.
Your work demonstrates a lot of thought, work and preparation.
Keep it up!