Data from: Experimental illumination of a forest: no effects of lights of different colours on the onset of the dawn chorus in songbirds

Da Silva, Arnaud, Max Planck Institute for Ornithology

de Jong, Maaike, Nederlands Instituut voor Ecologie

van Grunsven, Roy H. A., Leibniz Institute of Freshwater Ecology and Inland Fisheries

Visser, Marcel E., Nederlands Instituut voor Ecologie

Kempenaers, Bart, Max Planck Institute for Ornithology

Spoelstra, Kamiel, Nederlands Instituut voor Ecologie

Published Dec 08, 2016 on Dryad. https://doi.org/10.5061/dryad.437t2

Cite this dataset

Da Silva, Arnaud et al. (2016). Data from: Experimental illumination of a forest: no effects of lights of different colours on the onset of the dawn chorus in songbirds [Dataset]. Dryad. https://doi.org/10.5061/dryad.437t2

Abstract

Light pollution is increasing exponentially, but its impact on animal behaviour is still poorly understood. For songbirds, the most repeatable finding is that artificial night lighting leads to an earlier daily onset of dawn singing. Most of these studies are, however, correlational and cannot entirely dissociate effects of light pollution from other effects of urbanization. In addition, there are no studies in which the effects of different light colours on singing have been tested. Here, we investigated whether the timing of dawn singing in wild songbirds is influenced by artificial light using an experimental set-up with conventional street lights. We illuminated eight previously dark forest edges with white, green, red or no light, and recorded daily onset of dawn singing during the breeding season. Based on earlier work, we predicted that onset of singing would be earlier in the lighted treatments, with the strongest effects in the early-singing species. However, we found no significant effect of the experimental night lighting (of any colour) in the 14 species for which we obtained sufficient data. Confounding effects of urbanization in previous studies may explain these results, but we also suggest that the experimental night lighting may not have been strong enough to have an effect on singing.

Usage notes

Recordingdata2013allspecies

The data was collected in the field from 15 April to 15 May (from 27 April to 15 May for the Voorstonden location). The first column shows the 7 sites (from 1 to 7) used in the models as random effects. Site 1 corresponds to a location called ‘Lebret’s Hoeve’, site 2 to ‘Voorstonden’, site 3 to ‘Radio Kootwijk’, and site 7 to ‘Hijkerveld’. Sites 4 and 5 are adjacent spatially and correspond to a location called ‘ASK Doornspijk’. Finally, site 6 consists of two sites merged together because they overlap in a location called ‘Klaterweg’. The onsets (column 7) have therefore been obtained from the mean onsets in the two former sites for each light treatment on each day. The second column shows the 3 levels of 'Treatment', which represents the transects where the data has been collected (green, red, or white light transect). The third column shows the 'Formal date', i.e., the date at which the bird was singing (in calendar days). The fourth column shows the (relative) ‘date', which is the date relative to 15 April (0 = 15 April), and which has been used in the models as a random slope. The fifth column shows the 'onset relative to control'. This variable is calculated for each species, at each site and on each day, as the difference (in min) in the onset of dawn song between each light treatment (red/green/white) and the dark control. The sixth and last column shows the 'species' for which the onset is shown (14 levels, vernacular names shown).

DaSilvaetal_data.xlsx