Metacognition is said to be the ability to perceive one's own mental states (Metcalfe & Kober, 2005). It can also be more objectively defined as the ability to judge one's chances of success or failure at a task before actually performing it (Jozefowiez, Staddon, & Ceretti, 2009). For centuries, metacognition has been claimed to be uniquely human; but, it may be that animals exhibit this ability as well. Metacognition has recently been reported in several different animals including monkeys, orangutans, dolphins, and rats. In pigeons, however, no conclusive evidence has yet been found. Our study sought to see if pigeons can exhibit metacognition: specifically, can pigeons use their knowledge to guide their future behavior? We presented four birds with a same-different discrimination between arrays containing either few (2, 3, 4) or many (8, 9, 10) items. We know that pigeons' performance is good when the arrays contain a large number of items, but poor when the arrays contain only few items. In this experiment, we will include an "increase" button that the pigeons can use to increase the number of items in the array. When the number of items is small, if the birds know that they do not know the correct answer, then they should peck at the "increase" button in order to obtain more information. Once the number of items is large enough for the birds to know the answer, they will have to hit a "decision" button and then choose either Same or Different. When the number of items is large at the beginning of the trials, the birds should not need to use the "increase" button; so, they should go directly to the "decision" button and then choose either Same or Different. This and other studies on metacognition would help to provide insight into the evolution of the mind and a foundation for investigating neurobiological mechanisms of advanced cognitive abilities (Crystal & Foote, 2009).