I usually don't like to use flash when shooting animals or birds because the lighting looks artificial (which it is, of course). I prefer a more natural look, but in some instances flash is necessary. In this shot of a killdeer nesting on my property, I used flash because I wanted more depth of field than i could have had otherwise. The light was low and I was using a telephoto lens, thus the front of the bird would have been sharp while the tail featrues would have been soft. Because I used a flash, I was able to use f/22 with the 200mm focal length.