Dawn and dusk chorus as a potential zeitgeber

Over millennia, environmental light-dark cycle provided a dependable indicator of time of day. It showed the effects of light on physiology and behaviour in every animal. Furthermore, sunrise and sunset (dawn and dusk) usually refer to the duration of day length when the upper edge of the sun's disk is on the horizon. Interestingly, before the onset of sunrise and after sunset there is twilight (dawn and dusk), during which there is natural light provided by the upper atmosphere. Evidences suggested that transitions (twilight) are more essential to synchronize organisms circadian (circa = about; dian = day) and circannual (circa = about; annum = year) rhythms (seasonal events). Overall, we say that all the characteristics of light pose major changes in the behavior and physiology of animals and plant system. In this mini-review, we discuss the noteworthy aspects of dawn and dusk chorus and the behavioural changes observed during this switching between day and night times.