Depth of Field for shots of birds

I was using a Canon S 2IS with my optical zoom trying to shoot pictures of birds in the back yard at 4.5 and was not in focus exactly. Would I do better to try and use 8.0 and make the other adjustments to give me more flexibility on the focus point? Advice appreciated.

This applies to all subjects and just not birds. If you think that you are going to have a hard time nailing the focus exactly where you want a higher f-stop will give you some allowance on getting the perception of more in focus. This is relative to the distance that you are to your subject as well. The closer you are to your subject at a lower f-stop, the shallower the depth of field. I don't have any experience with your camera but I would think that if your DOF is giving you the focus field that you want then you should go up a stop or two. Remember to keep your eye on your shutter speed as it will drop proportionately to the changes in your aperture. You can always compensate this with a change in the ISO. The other variables in all of this is whether your subject is sitting still or moving and that adds another whole new dimension to how you manage the settings on your camera.