Good lens for bird photography?
Ah this one is a very good lens for birding.. Looking at the quality of the feathers on the blue bird.
Since you asked a very general question about which lens is good for bird photography, the answer is that a telephoto prime or telephoto zoom will be good enough.
The problem is how close can you get to the bird.
Here is a link which is very informative about the lens focal length required and respective bird size.
This will give you a general idea on what you need to get.
Most start off with a 300mm, 400mm small aperture prime lens with a TC14 and will usually get longer lenses as their hobby / passion progress from here.
As for which brand and model is better, you will need to look it up yourself as to which make of camera you are using.