Birds move around quickly. I have seen many photographers take one image only to examine and admire that image on the rear screen or through the view finder. Then they take another image and do the same. The problem with that is that for every second that you are looking at an image already taken you are missing the opportunity to take more images, possibly even better images. In bird photography many little things can make a big difference. An open beak, outstretched wings, it's angle, a head tilt, where the bird is looking, and a hundred other things impact the success of the image. By shooting only one image at a time and wasting time to look at it we are missing out on shooting more images. My advice is simple, shoot, shoot, shoot. Yes, just keep on shooting as long as the bird is there. Now I am not suggesting shooting thousands of identical images of a bird just sitting there doing nothing. Obviously, I am talking about moving birds. Just look at all the different images a person can get by just shooting and shooting:

Someone may argue, "but surely, you have to check your exposure and your focus. What is the point of having more images if they are all out of focus or wrongly exposed?" I get the argument. But can we not look at the histogram in the viewfinder to ensure correct exposure? Can we not look at the camera's focus indicator in the viewfinder (the focus block turns green when focus is locked)? If you don't trust these, then sure, look at one image, but please don't look at every image you take. Just shoot, shoot, and shoot.