Initially you have to keep your shutter speed as high as possible to avoid motion of the birds which will led to a firm photograph of the bird.
One of the biggest concern is that flapping wings.
It leads to unstability in the photograph. One thing you should note is that not all birds flap their wings at the same rate. There are too many variations. Never consider a photograph of a bird blur if the bird is in a movement.
The smaller the bird, more they flap their wings.
Example: A humming bird flaps its wings at an average of 50 flaps per second, some even flap more than that.
Large birds don’t flap their wings most of the time, probably thet flap their wings not more than twice a second and even though they flap, they flap it pretty slowly and easily, which is enough to grab a photograph very quickly.
The thing is your shutter speed should be more and your focus should be only on the the bird you are trying to capture at.
Most probably Sea Gulls are pretty easier for practice. They don’t even flap their wings most of the time.
Also it is easy to spot them in view finder as well.
Don’t forget, when you track a bird in viewfinder, make sure that you also keep its wings in frame.
Note:Settings should be changed as per environment.
Location: Arabian Sea.