Strictly speaking, of course, it's about pigeons. Look at what the Internet says:

Make some efforts to understand "pigeon science", if you want to learn from the apocalypse of pigeon garden, it is difficult to understand.

The so-called difficulty is not only that it is difficult to make any mistakes in all aspects of planting, breeding, training and competition.

It is even harder to know the racing pigeons in your hands. There are many good pigeons. ...