The effect of artificial light with different SPDs and intensities on the sleep onset of silvereyes

ABSTRACT

In recent years, artificial light at night brings increasingly severe impacts on natural ecological environment. Researchers have found that different species of migratory birds react differently to artificial light at night and each kind needs to be specifically studied. Tianjin City is an important stopover of the international bird migratory routes while having rapid growing light pollution. It is necessary to conduct target research for the representative bird species in this area. Silvereye, the typical type of migratory bird in Tianjin, was chosen as the experimental subject for the study. 15 subjects’ chirping frequencies were documented under natural light and the artificial light with different spectral power distributions (SPDs) and intensities. The sleep onset time was determined by the end of chirping. The results showed that the tested white light, 620nm orange and 580nm yellow light significantly delayed the silvereyes' sleep onset while light in 470nm blue or 510nm green showed slight interference. The higher the irradiance level of light was, the longer the sleep onset would be postponed. The study leaves references for lighting design of urban ecological areas on minimizing the negative impacts of artificial light to silvereyes’ sleep behavior.

KEYWORDS:

• Light pollution
• artificial light at night
• migration period
• sleep onset
• chirping

Acknowledgements

The authors will send sincere appreciation to Dr. Xinlong Ma and Dr. Jianxiong Ma from Tianjin Hospital, for assisting the experiments to be accomplished in an ethical and responsible manner.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Key Research & Development Program in the thirteenth Five-year Plan under Grant 2016YFC050290202; National Natural Science Foundation under Grant 51678400.