Impact of artificial light on night-time singing behaviour of the swifts

Abstract

In this study, we explored the effect of artificial light on night-time singing behaviour of the swifts in Summer Palace, Beijing, China. In the summer of 2015, we tested the night-time singing frequencies of the swifts under full-spectrum white, 437.5 nm violet, and 622.5 nm orange light at 5 mW/m2, 20 mW/m2, and 50 mW/m2. It revealed that white and orange light significantly increased the average singing frequency, while violet light pronouncedly raised the singing frequency only at 50 mW/m2. The variations in impacting rhythms of the tested light sources leave references for bird-friendly exterior lighting schemes.