That's a Wheaten color you see in the background.
The best to do is photograph her whole body, like the last photo, but on a sunny day in the summer or late spring.
Exactly as you see it
Get the bird in some light, but make sure the light (preferably sun is at a high angle/elevation otherwise you'll get more white sheen than iridescence. Make sure your camera gets good color too because a camera's ability to capture high quality, high spectrum color is...