I suspect most of the time the birds you are trying to take photographs are far from the camera and are at the Infinity distance of the lens. Therefore it is best to come out of auto focus as it will struggle to find a point of interest with fast moving subjects. With the camera in manual focus, set the lens to infinity, because it is set to infinity then there is no need to use a small aperture for maximum depth of field and a higher shutter speed to capture the action, remember to select a higher 'film' speed for action photography.
There is also something called hyperfocal distance which if the lens on your camera has the markers can help you to set the maximum depth of field for a chosen aperture, read here, hyperfocal distance.
Using the camera in manual modes or Shutter or Aperture priority modes will help you understand your camera and photography better. Auto modes can be useful at times but should not be relied upon, especially auto focus, you do not need it for distant subjects.
Always make a mental picture of the shot you are looking for and then you can decide which are the best settings on the camera to apply for this shot, you can then concentrate on selecting the best vantage point and monitoring the birds behaviour to see where the best combo of viewpoint and camera setting may get you 'that' shot.
Be very patient.
Digital photography is great because you are not constrained by having only a certain amount of frames
as with a roll of film but it is quite a good discipline to shoot as if you only have a certain amount of frames
to shoot with, this will allow you to refine your technical proficiency and improve your intuition for predicting
the best shots. Too often people go machine gunning a scene/ subject or event and come back with images that have no artistic or meaningful merit and spend hours and hours having to edit and reject without learning anything.
