I wake to a grey haze that my brain insists is daylight – but when I check my phone it’s only 3am. I lie on, listening to a robin singing – another diurnal creature whose circadian cycle is upset by the new white LED (light emitting diode) streetlight outside my house. At 4am, I give up on sleep.
Outside, other than my own footsteps, the only sound is more robin song as I go walking. In winter, robins are one of the few avian species still singing, their ranks swollen by territorial females as well as males. Their winter song is languid and tremulous. However, approaching the glare of an LED lantern, I notice an uptick in my pace that seems to chime with a greater stridency coming from the singing robin in an adjacent sycamore.