As others have pointed out, correctly, tracking fast-moving birds is a lot more to do with skill and technique than the camera used. Learning to find the bird in the finder, keep it framed while panning, and getting the camera settings correct to boot, takes a high degree of skill and practice - it can come to you, mostly by trial and error, and constant practice.
There are two factors involved with fast-moving birds in flight - and the panning is generally the most vital - this is all on the photographer, rather than the camera. More focus points and better predictive focus algorithms might help slightly, but it's still up to you to find the bird, move with the bird, and being ready for directional changes. Even basic, entry level DSLRs can get the shot, if the photographer can keep up with the panning.
The second factor, and really the only one where the camera's ability comes more into play, is when the bird is moving towards or away from you, during which the camera's focus system will have to be constantly adjusting the focus as the subject draws closer - the faster the bird, the harder it becomes for an older, slower-focusing camera or older, screw-drive lenses. It's still by all means possible, but you can see an improved ratio of keepers with some of the faster-focusing cameras and a good lens. It still requires the photographer to keep the focus point or points on the bird, and still pan with any directional changes...so that skill is still a necessary part of the equation. And choosing the right settings is still crucial, again this is the photographer's responsibility...making sure the shutter speed was fast enough, making sure you chose the right focus area for the subject, making sure you chose continuous AF tracking for a closing subject, making sure the exposure is correctly set and being able to correct it on the fly for changing background light conditions, and so on. So even with a super-fast, predictive AF-tracking camera and top of the line fast lens, the photographer's skill and experience are still going to be by far the most important factor to get the shot.
Start with slower birds in flight, get good at tracking, get comfortable with your camera's controls and settings, understand how it tends to meter in different conditions, and figure out which focus points to engage in different situations. Gulls, big waders, soaring raptors tend to be easiest...then work towards faster but consistent, straight-line flyers like ducks, cormorants, chunkier birds. Eventually, you can gain enough skill to start tracking the fast birds, even the really challenging buggers like swifts and swallows and sparrows - tiny, super-fast, and constant, unpredictable directional changes.