What about the space behind the bird? In many bird pictures it is good to have the background out of focus—way out of focus. An out of focus background usually sets the bird apart from the background and draws viewers’ attention to the bird. This is typically considered a positive thing. The further the background is from the bird, the more out of focus it will be. In addition, the wider an aperture you use, the more out of focus the background will be. Many bird photographers strive to get a background that is so blurry, it has a creamy, soft texture. This is referred to as bokeh. Quality bokeh can also be affected by the quality of the lens you are using.
Here’s an example of bokeh in this image of a Common Yellowthroat. The upper part of the background is sky while the lower part is blurred out green and, light colored grass, which actually extends up into the lower part of the blue sky above the bird. You can tell that some of the light colored grass behind the bird was closer than the green grass as it’s not quite as smoothly blurred. I took this shot from about 25 feet at f7.1. According to DOF tables there should be about 3 inches of DOF. Everything in front of and behind the DOF is out of focus. The metal perch is in focus where the bird is but you can see where it starts to blur as it extends further behind the bird. The part of the metal that is blurred is behind the DOF area. The further behind the DOF the more blurry things get.
This leads us back to searching for that perfect perch that you hope a bird lands on. As you are walking or driving along, keep an eye out for a perch that has light coming from a good direction, that maybe has color or texture to it, and that has a background where whatever is behind it is as far away as possible.
And of course, all rules are meant to be broken, some say! There are legitimate reasons to want the background in a photo to be just behind the bird and in focus. Many habitat or behavorial shots of birds depict birds’ everyday habitats and surroundings. It’s all up to the photographer and what he/she wants to communicate to their viewers. My portfolio includes some images with a blurred out background while others are habitat or behavioral shots. Take them all when you’re out shooting and display a variety in your own portfolio.