I would use Shutter priority mode and center AF point. I would also turn VR off as it will slow down AF. I would also choose AI SERVO Mode or whatever it is Nikon has. Also use back button focus so you can control AF independently from the shutter release. You can practice panning on cars simply to get used to moving the camera while engaging AF seamlessly, but birds are much much harder than cars and much much more erratic. The hardest part will be to even get them into the viewfinder and keep them in the viewfinder as long as possible. That is only going to come from practicing on birds, not cars. Try to watch your subject as much as possible. Sometimes movement can be predicted. For instance, if a bird is constantly returning to a nest it is building and then flying out to grab more supplies before returning. You can sit and predict those movements. Also, keep both eyes open as you swing the camera towards the sky to locate the bird. It makes it easier to locate it then simply keeping 1 eye to the viewfinder.