Pushing the reset button on nature’s alarm clocks

Posted by Ellery McNaughton @EJ_McNaughton

Sunrise_red-yellow_glow

Some birds don’t seem to care that dawn frequently looks nicer than it feels

I struggled in achieving the Herculean feat of getting up before dawn today. Fortunately for me, I had help – my local tūī (Prosthemadera novaeseelandiae) decided to serenade the neighbourhood, a sound far more pleasant than the alarm on my phone. Not everyone is so appreciative, especially when the ‘dawn chorus’ begins well before its name would suggest.

Timing of dawn song is influenced by a number of natural factors. For example, studies have shown that rain, noise from nocturnal insects, intensity of moonlight, and even individual personality can advance or delay the onset of dawn song. Of course, factors such as noise and light intensity can also be introduced into the environment as a result of human impact and urbanisation.

The onset of dawn song has been found to be much earlier for urban birds than for their rural counterparts, a difference attributable to traffic noise and artificial light at night (ALAN).

Singing tui

Snooze button nowhere to be found. Photo credit: Tony Wills

Urban birds have been found to sing earlier in the morning when exposed to traffic noise. And it’s not just road vehicles – birds near airports also advance their singing to avoid peak aircraft traffic in the morning. ALAN has also been linked to advancing morning bird song. There are many sources of urban ALAN, but a large proportion comes from streetlights. The effects of different types of streetlights on the timing of urban bird song is not yet fully understood, although there have been some indications that different technologies can have varying effects on different species.

This is the area that I’m interested in for my research. I hope to determine whether changing the streetlights from orange (high-pressure sodium) lights to white (light emitting diode) lights makes my local alarm clock start serenading earlier or later in the morning. Coincidentally, I am also forever grateful to the inventors of audio recorders for enabling bleary-eyed ecologists to sleep through their data collection.

Ellery McNaughton is a PhD student in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. Her project will investigate the effects of a city-wide changeover in streetlight technology on urban bird behaviour and ecosystem function. She is supervised by Margaret Stanley, Jacqueline Beggs, Kevin Gaston(University of Exeter, UK) and Darryl Jones (Griffith University, Australia).

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