Tripods and gimbal heads
If you're using a telephoto lens, a tripod is pretty much indispensable. The heavier the lens, the harder it is to keep it still. That's why a heavy, robust tripod is a real must-have. Besides tripods, there's also a certain kind of tripod head that is ideal for photographing (fast-moving) animals: the gimbal head.
A gimbal head is a tripod head that means a camera & telephoto lens combination is supported at its natural balance point. Simply put, it is a tripod head that comprises an L-shaped bracket with a swing arm. The lens plate is attached at the lowest point of the swing arm. The camera & lens combination then hangs 'in' the gimbal head as it were. Once you mount the combination and let go, if properly aligned, it will be in perfect balance. This is really handy when you need to act fast, e.g. when photographing birds or other animals.