Singing from North to South: Latitudinal variation in timing of dawn singing under natural and artificial light conditions.

摘要: Summary 1. Animals breeding at northern latitudes experience drastic changes in daily light conditions during the season with decreasing periods of darkness, whereas those living lower are exposed to naturally dark nights throughout year. Nowadays, many animals also artificial night lighting (often referred as pollution). 2. strongly rely on variation levels time their and seasonal behaviour. Previous work passerine birds showed that leads earlier onset dawn song. However, these studies were carried out intermediate more limited daylength, we still lack an understanding impact relation natural conditions. 3. We investigated influence timing singing five common songbird species each three regions Europe differed daylength (northern Finland, 65°N; southern Germany, 48°N; Spain, 37°N). In region, selected peri-urban forest sites without street lighting, recorded beginning local season. 4. Our results show earliest singers, i.e., European robins (Erithacus rubecula) blackbirds (Turdus merula), started along increase brightness no additional effects lighting. contrast, later great tits (Parus major), blue (Cyanistes caeruleus), chaffinches (Fringilla coelebs), similar onsets song relative sunrise across all latitudes. 5. Artificial affected tits, even Finland where became very bright. Proximate factors such differential sensitivities may explain why early singers plastic behavioural responses artificially bright nights. The maintenance rhythmicity late under be adaptive response predation risk or costs sleep loss. This article is protected by copyright. All rights reserved.