Thanks @AnneAulsebrook. So light at night keeps pigeons awake but the colour of the light (white/amber) does not make a difference.

What about sleep in other birds? Does the colour of light matter?

We looked at the #AustralianMagpie for answers. Pic: @DougGimesy #SCBMelb20

Magpies are common residents of Australia's light polluted cities, and despite their “angry” reputation ( #swoopingmagpie) are great to work with.

Magpies were kept in aviaries at @latrobe and were exposed to LED lights; but only part of the night (4 h).
#SCBMelb20

Like @AnneAulsebrook ‘s pigeons, light at night disrupted all aspects of sleep measured.

When lights were on at night, magpies slept less, slept less intensely, and woke more often.

After lights were turned off, magpies slept more and more intensely.

#SCBMelb20

So, was amber light better for magpie sleep?

Yes! Under white light magpies slept 1 hour less than under amber light, and then slept more the next day to make up for it.

Our results are now published in @CurrBiol: https://doi.org/10.1016/j.cub.2020.06.085

#SCBMelb20

The colour of lights does not matter to pigeon sleep, but it does to magpies. So while a one size fits all solution would be nice, for the urban light problem that's not gonna work. Lights affect wildlife differently so as a rule, turn off unnecessary lighting. #SCBMelb20