Daily and Seasonal Patterns in the Singing Activity of Birds in East China

The vocal behaviour of birds can change daily and seasonally. Understanding the daily and seasonal acoustic activity patterns of birds helps to understand their behavioural ecology and is crucial for designing effective monitoring protocols. We studied daily and seasonal acoustic activity patterns for a complete annual cycle of three bird species: Alström's Warbler Phylloscopus soror, Brownish-flanked Bush Warbler Horornis fortipes and Streak-breasted Scimitar Babbler Pomatorhinus ruficolli at three different sites in Yaoluoping National Nature Reserve, Anhui Province, East China. All three species displayed a peak in singing activity in the morning; however, they differed in their acoustic activity during the daytime. Alström's Warbler was vocally active for five months (April–August), with higher singing activity earlier in the season. Brownish-flanked Bush Warbler was vocally active for six months (March–August) and showed a significant variation in singing activity over time. Streak-breasted Scimitar Babbler was vocally active for nine months (March–November) and displayed a slight variation in singing activity among months at different sites. The acoustic activity of the Alström's Warbler and Brownish-flanked Bush Warbler was negatively correlated with precipitation, whereas in Streak-breasted Scimitar Babbler there was no relationship with precipitation. Overall, we found large temporal variation in singing activity within a day and between seasons. To better understand the function of the daily and seasonal pattern of singing, future studies should investigate the functioning of different song types used during daytime and morning.