The #3 post so far this year explored how zebra finches reward themselves for singing well:
Dopamine is an important hormone released from neurons involved in reward pathways. Researchers at Cornell University wanted to know if dopamine signaling was involved in how birds learn songs. Their findings, recently published in Science, present evidence that neurons in the brain of zebra finches do in fact decrease dopamine signals when the birds hear an error in their song in comparison to when they sing 'correctly'. The researchers also found that dopamine signaling was enhanced when the birds corrected a mistake made during a prior attempt.
Sources:
V. Gadagkar, P.A. Puzerey, R. Chen, E. Baird-Daniel, A.R. Farhang, J.H. Goldberg. Dopamine neurons encode performance error in singing birds. Science, 354:1278-82, 2016.
Video from YouTube