Behavioural plasticity in the onset of dawn song under intermittent experimental night lighting

Abstract

The disruption of daily rhythms is one of the most studied ecological consequences of light pollution. Previous work showed that several songbird species initiated dawn song earlier in areas with light pollution. However, the mechanisms underlying this shift are still unknown. Individuals may immediately adjust their timing of singing to the presence of artificial light (behavioural plasticity), but the observed effect may also be due to phenotype-dependent habitat choice, effects of conditions during early life or micro-evolution. The main aim of this study was to experimentally investigate how males of four common passerine species respond to day-to-day variation in the presence of artificial night lighting in terms of the timing of singing. During two consecutive breeding seasons, we manipulated the presence of light throughout the night in a cyclic fashion in several naturally undisturbed forest patches. We show that individuals of all four species immediately and reversibly adjusted their onset of dawn singing in response to artificial light. The effect was strongest in the European robin, but relatively small in the blue tit, the great tit and the blackbird. The effect in the latter two species was smaller than expected from the correlational studies. This may be coincidence (small sample size of this study), but it could also indicate that there are longer-term effects of living in light-polluted urban areas on timing of dawn singing, or that birds use compensatory behaviours such as light avoidance. We found no evidence that our light treatment had carryover effects into the subsequent dark period, but robins progressively advanced their dawn singing during the light treatment.

Exposure to predator models during the fertile period leads to higher levels of extra‐pair paternity in blue tits

“…Other factors may similarly influence paternity by constraining or enhancing extra‐pair mating behaviour. For example, artificial light at night has strong effects on the behaviour of wild birds at dawn, in particular on the seasonal and daily timing of dawn singing (da Silva, Samplonius, Schlicht, Valcu, & Kempenaers, ; da Silva, Valcu, & Kempenaers, ) and on male extra‐pair siring success (Kempenaers et al, ). A greater focus on behaviour that leads to extra‐pair and within‐pair copulations, and factors that inhibit, constrain or enhance these behaviours, might help explain the observed variation in rates of extra‐pair paternity.…”

Impacts of artificial light at night on sleep: A review and prospectus

“…Moreover, light pollution has become a rapidly increasing and global phenomenon (Davies & Smyth, ; Falchi et al., ; Kyba et al., ), prompting concerns about the possible negative impacts of ALAN on sleep in humans (Czeisler, ; Erren & Reiter, ; Navara & Nelson, ; Pauley, ; Stevens & Zhu, ; Stevens et al., ) and wildlife (Dominoni, Borniger, & Nelson, ; Dominoni, Goymann, Helm, & Partecke, ; Gaston et al., ; Randler, ). In species that sleep predominantly at night, sleep is particularly likely to be disrupted by ALAN, and there is now evidence that diurnal songbirds exposed to ALAN commence their activity earlier (Da Silva, Samplonius, Schlicht, Valcu, & Kempenaers, ; Da Silva, Valcu, & Kempenaers, ; de Jong et al., ; Kempenaers, Borgstrom, Loës, Schlicht, & Valcu, ; Nordt & Klenke, ; Spoelstra, Verhagen, Meijer, & Visser, ; but see Da Silva et al., ) and are active for longer each day (Da Silva, Diez‐Méndez, & Kempenaers, ; de Jong et al., ; Dominoni, Helm, Lehmann, Dowse, & Partecke, ; Russ, Rüger, & Klenke, ). The intensities of ALAN experienced by some urban birds, mammals, and fish (approximately 0.3–1 lx.)…”

European Blackbirds Exposed to Aircraft Noise Advance Their Chorus, Modify Their Song and Spend More Time Singing

“…In such cases, there is likely a compound effect of artificial lighting and anthropogenic noise, which are not always easy to tear apart. When acoustic and light pollution occur simultaneously, light seems to have a stronger impact over the advance of dawn song than noise (Nordt and Klenke, 2013;Da Silva et al, 2016), but birds also advance dawn chorus near large airports in places where artificial lighting is absent (Dominoni et al, 2014(Dominoni et al, , 2016Gil et al, 2014).…”