Early Birds by Light at Night: Effects of Light Color and Intensity on Daily Activity Patterns in Blue Tits

Maaike de Jong (Corresponding author), Samuel P. Caro, Phillip Gienapp, Kamiel Spoelstra, Marcel E. Visser

Research output: Contribution to journal/periodicalArticleScientificpeer-review

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Artificial light at night disturbs the daily rhythms of many organisms. To what extent this disturbance depends on the intensity and spectral composition of light remain obscure. Here, we measured daily activity patterns of captive blue tits (Cyanistes caeruleus) exposed to similar intensities of green, red, or white light at night. Birds advanced their onset of activity in the morning under all light colors but more under red and white light than under green light. Offset of activity was slightly delayed in all light colors. The total activity over a 24-h period did not change but birds moved a part of their daily activity into the night. Since the effect of red and white lights are comparable, we tested the influence of light intensity in a follow-up experiment, where we compared the activity of the birds under different intensities of green and white light only. While in the higher range of intensities, the effects of white and green light were comparable; at lower intensities, green light had a less disturbing effect as compared with white light on daily rhythms in blue tits. Our results show that the extent of this disturbance can be mitigated by modulating the spectral characteristics and intensity of outdoor lighting, which is now feasible through the use of LED lighting.
Original languageEnglish
Pages (from-to)323-333
Number of pages11
JournalJournal of Biological Rhythms
Issue number4
Publication statusPublished - 26 Jul 2017


  • NIOO

Research theme

  • Global environmental change
  • Restoration ecology


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