Evolutionary Origin of Nocturnality in Birds

Abstract

The diel activity patterns of living animals are observable, whereas knowing about those patterns in ancestral or extinct animals remains a challenge. Differences in the diel activity patterns of animals may have led to morphological and genetic differences in their visual systems. Recent developments in reconstructing the traits of ancestral animals offer the opportunity to improve our knowledge of the diel activity patterns of ancestral animals. One of the most important findings is the nocturnality of the common ancestors of living birds. Accumulating evidence based on morphological, behavioural and molecular data suggest the potential importance of nocturnality in their early evolution. The nocturnality of birds may be traced back to theropod dinosaurs and ancestral archosaurs. The possible long‐term history of nocturnality of these diapsid lineages, which parallels that of synapsid lineages (e.g. ancestral mammals), may have facilitated the evolution of mammal‐like characters (e.g. endothermy) in birds. Key Concepts Diel activity patterns are basic features of animal behaviour, and knowledge of the diel activity patterns of animals is important for understanding their evolutionary history. Living birds widely show at least some form of partial nocturnal activities during their life cycles. The common ancestor of living birds may have engaged in considerable nocturnal activities. There may have been a long evolutionary history of nocturnality in diapsid lineages, paralleling that found in synapsid lineages (e.g. ancestral mammals). Nocturnality may have shaped the evolution of diapsid lineages (e.g. birds).

Molecular phyloecology suggests a trophic shift concurrent with the evolution of the first birds

“…Moreover, one recent study shows that the CALB was probably cathemeral (i.e., active in both day and night), and that it may have evolved an enhanced visual capability to detect motion 30 . Cathemerality is considered to be linked to high predation risk 102,103 and the promoted motion detection ability of the CALB may mainly help to detect approaching predators 104 given its herbivory. Therefore, the dietary shift may have made ancestral birds become the prey of high-level consumers, possibly leading to their high predation risk.…”

Cathemerality: a key temporal niche

“…Increasing recognition of the importance of the temporal niche in evolution has stimulated the phylogenetic reconstruction of activity patterns of early mammals (Roll et al ., 2006; Maor et al ., 2017; Baker & Venditti, 2019), as well as birds (Wu & Wang, 2019; Wu, 2020), geckos (Gamble et al ., 2015; Pinto et al ., 2019) and skinks (Slavenko et al ., 2022). For much of the Mesozoic mammalian [as well as gecko (Gamble et al ., 2015; Pinto et al ., 2019) and skink (Slavenko et al ., 2022)] activity was restricted to the nighttime due to competition with and threat from largely diurnal dinosaurs – known as the nocturnal bottleneck (Gerkema et al ., 2013; Maor et al ., 2017).…”