Delayed gratification: A grey parrot (Psittacus erithacus) will wait for a better reward 

African Grey parrots can show self-control and wait to obtain a better reward

Source: Koepke A.E, Gray S.L., Pepperberg I.M.
Journal of Comparative Psychology, Vol 129(4), Nov 2015, 339-346.

Delayed gratification means being able to wait to obtain a superior reward, rather than immediately taking an inferior reward. It’s seen as showing that an individual can think ahead, and use self-control, and it has been studied in humans, especially children, as well as non-human animals.

An experiment has shown that an African Grey parrot is capable of waiting to obtain a better reward for up to a quarter of an hour, in other words, the parrot had the capacity for delayed gratification. The bird was first taught how to use English, and then told to ‘wait’. The parrot was able to wait for rewards that it could see, as well as those hidden by the researchers.