title: 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.
authors.affiliation: Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Eberhard-Gwinner-Strasse, 82319 Seewiesen, Germany.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Da Silva
authors.affiliation: Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Eberhard-Gwinner-Strasse, 82319 Seewiesen, Germany.
authors.forename: Mihai
authors.initials: M
authors.lastname: Valcu
authors.affiliation: Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Eberhard-Gwinner-Strasse, 82319 Seewiesen, Germany b.kempenaers@orn.mpg.de.
authors.forename: Bart
authors.identifier: http://orcid.org/0000-0002-7505-5458
authors.initials: B
authors.lastname: Kempenaers
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D004784:Environmental Monitoring; D004787:Environmental Pollution / Q000009:adverse effects*; D005060:Europe; D008029:Lighting / Q000009:adverse effects*; D020308:Songbirds / Q000502:physiology*; D013045:Species Specificity; D014828:Vocalization, Animal / Q000502:physiology / Q000528:radiation effects*; D014887:Weather
keywords: artificial night lighting; dawn chorus; dusk chorus; seasonality; song production; weather