Yellow. According to the information of Sougou World, 202 1, the anklet of Japanese carrier pigeons is yellow, which is made by the carrier pigeon association, including the color and size of the anklet. The anklet made by the carrier pigeon club is the carrier pigeon's ID card, which records all the information of the carrier pigeon, including the owner's name, the carrier pigeon's feeding position, the coordinates of dovecote, and the contact telephone number. Only pigeons with anklets are eligible to participate in the competition.