Wild bird photography.
A subject only for the very patient among us as this type of photography requires many hours of just sitting hidden from view in the hope of capturing that image of a bird. 1st, a really good telephoto lens is essential, I find that on many occasions my 120-400 is too small, but the price of say a 600mm blows your mind away. The faster the lens the better too, but again the price!!.
I always choose bright sunny days for high shutter speeds and find this works well. 2nd, learn about the bird/s you wish to photograph. Some are easy like the summer visitors such as the Swallow or House Martin because they nest in convenient places for us to take pics of them. Just set up on your tripod pointing at the nest and just wait for the bird to appear, and it will. The males usually perch close to the nest on say a fence or wires and are good to snap. Number 1 priority; NEVER ALARM THE BIRDS. They may desert the nest and any young will die. 3rd, some birds are quite tame and will approach if you offer food during nesting time, a good time to take your pic if you stay back and wait. Patience is a vital factor with bird photography so only try it if you have plenty. Many birds are endangered so their welfare ALWAYS comes first, even if you don't get your pic and have observed a bird, then that is a privilege. Space does not allow me to go into too much detail, but DO try bird photography, again, some big prints on your walls will impress your friends and give you a FGF, (feel good factor) , all the best.