I'm sure this is nothing new to most of you but thought i would post this series of a Kestrel i photographed yesterday. I thought it would make a great example to show how much difference your position makes in terms of the light and also the background.
    Note: I deliberately didn't use any fill flash in any of the images. All were taken with Manual exposure with 500mm lens. Also there is no PP work done at all beyond small crops to make the bird roughly the same size plus sharpening for web. No shadow/highlight/recovery etc.
    They were taken right in the middle of the day when the light was at its worst so whilst not the perfect tutorial hopefully you will get something from it.

    When i first approached the Kestrel (#1) I was below the bird (walking up a steep track) and the light was directly behind. In order to get correct exposure on the bird the background is completely washed out and the light is terrible. You can also tell that i am shooting UP at the bird.
    #2 - i was able to get higher up the track to a point where the sun was almost at right angles to the bird and i now had the ocean as the background. The background is much nicer and the light is getting better but still not great with shadows on the face etc.
    #3 - higher still and the bird is starting to turn its head more towards the light lessening the facial shadows and the background is now a nice green bush. I'm around the same height as the bird.
    #4 - I'm now a bit above the bird and directly behind and so moving myself more so the sun is closer to my angle but still not 100% behind me. Background is now the beach and reef (rock shelf). I must admit that i am quite partial to this background
    #5 & #6 - I am now as high and left of the bird as the track will allow. The extra height above the bird is nice (and not often easy to get) and the sun is as much behind me as it is going to get at that time (still quite high). The big difference between these two images is the background. #5 is terrible with the OOF sign, bush and grass all combining to make a distracting background. #6 was taken by moving only a metre to my left. A small movement which made a massive difference to the image. The background is now clean and even - no cloning whatsoever (No saturation/vibrance added either).

    So there are two main points that i think are worth thinking about.
    1. - watch the angle of the light
    2. watch the background and see if a tiny movement might make a big difference to the image - you might be surprised how often it does