This chapter details the organization of the avian circadian clock systems starting with the systemic levels of circadian organization that perceives the external cue (light) and then generates the timing. It has been shown that unlike the mammals, there are three different master clocks that regulate the timing and they are functionally organized in such a way that they produce synchronized events in daily life in birds. The molecular mechanism that generates the timing and then the mechanism by which the circadian clock is entrained to the external environment are discussed. Finally, the chapter explains the role of circadian clocks in the regulation of physiology and behavior of birds.
Cassone, V. M., Paulose, J. K., Harpole, C. E., Li, Y., & Whitfield-Rucker, M. (2017). Avian circadian organization. In Biological Timekeeping: Clocks, Rhythms and Behaviour (pp. 241–256). Springer (India) Private Ltd. https://doi.org/10.1007/978-81-322-3688-7_11