In addition to finding plain backgrounds to direct focus towards your subject, you can also use backgrounds that divide the scene into multiple spaces. Exactly how you divide the scene gets into questions of composition: how the scene is balanced, using the contrast in backgrounds to lead the viewer through the photo, etc. Without going down that road too far, I wanted to share some examples of backgrounds that divide a photo into different spaces.
The division between rocky coastline and the sea in this photo showcases the habitat of these Ruddy Turnstones, while also making them stand out. Also, you can imagine them being camouflaged, but they aren’t actually hidden in the photo.
A Laughing Gull stands on the pondfill sand near the Great Salt Pond. There’s a lot of contrast in this photo. The body of the gull stands out against the blue of the pond, while its feet stand out against the sand. (Note: The blue of the Great Salt Pond? Crazy, I know. It must have been some trick of the light.)
In this photo, piles of dry sargassum create a flowing band of sand around a Killdeer.
When using backgrounds to divide space, ideally you can create spaces that enhance the balance of the image and draw attention to the subject. You can see a clear difference in the two examples below. The Sandwich Tern seems to coast above the sloping hill (although the hill is actually far in the background), while the Great Egret is caught, a bit awkwardly, at the border of sky and hills.
It is worth noting that I am not at the ninja level of bird photography, anticipating when flying birds may align with distant hills. But, whether you are moving or your subject is moving, look out for angles that showcase a bird in the right spot on a divided background.