If I were only allowed to give you ONE tip to improve your bird photography, this would be that tip.
Point your shadow at the bird. Side lighting is cool for landscapes. Rembrandt style lighting is cool for portraits. Simple, straight-on, in your face, front lighting is cool for birds.
Staying on sun angle means that you will eliminate the harsh shadows that are caused by bird wings or beaks when the bird is side-lit. Simple front lighting also helps to define colors and to enhance the definition of the bird’s feathers.
Even the most vibrant bird will look rather drab and featureless with the sun off angle.
Unless you are shooting backlit, you should ALWAYS make sure the sun is over your shoulder when you are making bird photos. That means staying on sun angle. As the sun moves so should you. Remember to continuously check the sun direction.
Keep the sun behind you and the bird in front of you. You’ll make better bird photos than most of the people who casually post bird pictures online and you’ll do it by default.