At Lake Shinji in Shimane Prefecture, which is known as one of the leading wintering grounds for wild birds in Japan, males can be seen desperately appealing to females as the mallards enter the courtship season.
Many mallards fly around Shinjiko Green Park, a wild bird observation facility in Izumo City, and you can observe how they overwinter from autumn to spring.
Usually, it is a male mallard with a sober body color, but when the courtship period comes from January to February, it turns into bright green and white feathers called "reproductive feathers".
Many male mallards in Lake Shinji have also been replaced by reproductive feathers and are trying to attract females.
During the winter, paired mallards travel north for breeding after overwintering, laying eggs and raising children.