>>3088930Sunny days or time of day with ample sunlight hitting the bird will make flight pictures much more possible.
If you know where they hunt or frequent, that will make it easier to be ready. Depending on the length of your lens, you'll want anywhere from 1/320 to 1/800 or more if you can afford it to really freeze it in flight. Using constant AF is very helpful especially for moving subjects.
If you have a flash unit, it can be very helpful if you're within distance. A flash extender is also very inexpensive and popular among birding professionals. I use one and it really helps to bring out the details of birds in flight or at rest.
Good luck.
