Briefly describe how to use behavior training to make a pigeon learn to peck a small colored disc.

Hungry pigeons first, then put a grain of rice on a small colored disk for the pigeons to peck. After about 15 days, stick the rice grains on a small colored disc and let the pigeons peck. After about 10 days, draw the shape of a grain of rice directly on the small colored disc to make it look like a grain of rice. Pigeons will naturally pick out small colored discs and peck them. Pick it out and you'll have another one. This is the original bird training method used by Jianghu people to tell fortune with licensed birds.