Light pollution alters the phenology of dawn and dusk singing in common European songbirds

Abstract

Artificial night lighting is expanding globally, but its ecological consequences remain little understood. Animals often use changes in day length as a cue to time seasonal behaviour. Artificial night lighting may influence the perception of day length, and may thus affect both circadian and circannual rhythms. Over a 3.5 month period, from winter to breeding, we recorded daily singing activity of six common songbird species in 12 woodland sites, half of which were affected by street lighting. We previously reported on analyses suggesting that artificial night lighting affects the daily timing of singing in five species. The main aim of this study was to investigate whether the presence of artificial night lighting is also associated with the seasonal occurrence of dawn and dusk singing. We found that in four species dawn and dusk singing developed earlier in the year at sites exposed to light pollution. We also examined the effects of weather conditions and found that rain and low temperatures negatively affected the occurrence of dawn and dusk singing. Our results support the hypothesis that artificial night lighting alters natural seasonal rhythms, independently of other effects of urbanization. The fitness consequences of the observed changes in seasonal timing of behaviour remain unknown.

Night Light-Adaptation Strategies for Photosynthetic Apparatus in Yellow-Poplar (Liriodendron tulipifera L.) Exposed to Artificial Night Lighting

“…Over the past 100 years, for example, the nighttime light pollution caused by excessive amounts and indiscriminate diffusion of external lighting has emerged as an important environmental issue because of its adverse effects [2][3][4][5]. To elucidate how repetitive exposure to artificial night lighting affects photosynthetic pigments as a potential indicator of premature leaf senescence as well as yellowing and defoliation in newly initiated leaves, yellow-poplar seedlings were exposed to the natural day/night cycle and the day/night with artificial lighting cycle.…”

“…Nighttime light pollution generated by excessive external lighting has been demonstrated as an important environmental issue caused by adverse effects such as energy waste [1][2][3][4][5]. Notably, despite the fundamental importance of natural darkness, nighttime artificial lighting has become a globally widespread phenomenon causing light pollution [6].…”

Habitat type, food resources, noise and light pollution explain the species composition, abundance and stability of a winter bird assemblage in an urban environment

“…However, light at night is considered as a major driver of change in timing of daily activity. Light pollution effect has been studied mainly during the breeding period and in the context of extended vocal activity associated with displaying behaviour (Miller 2006;Da Silva et al 2015) and earlier development of reproductive system (Kempenaers et al 2010;Dominoni et al 2013). In contrast, the effect of artificial lights on the timing of behaviours during winter has received relatively little attention.…”

The effects of light pollution on biological rhythms of birds: an integrated, mechanistic perspective

“…Only a few studies have tried to overcome this limitation in the field to at least separate the effects of noise and light, while controlling for ambient temperature (Kempenaers et al 2010; Da Silva et al 2014. These have shown that light pollution can clearly alter the onset and offset of daily singing in a variety of species, and that the annual development of dawn and dusk chorus is accelerated under artificial lights (Da Silva et al 2015 ). In addition, Kempenaers and colleagues have demonstrated that artificial lights not only advance dawn song in the blue tit, but early singing associated with lights was positively correlated with the amount of extra pair offspring that males were able to sire, hinting at potential reproductive consequences of light pollution (Kempenaers et al 2010 ).…”