And that's OK, because in addition to having a delicate 30-year-old body actually complete menial weekend tasks, I'm also able to avoid the eerie, discombobulating early morning chorus of the songbirds. As if having the bar lights dialed up to tanning-bed-level brightness isn't sobering enough, stumbling out the front door into 4:30 AM Chicago and hearing bird chirps bounce around alleyways and off apartment buildings is a dizzying kind of surreal.
The "dawn chorus," as it's called, is a method for songbirds to both defend their breeding territories and attract mates—it's something like a Facebook poke or an OK Cupid wink if that helps you make sense of it. Those first few chirps of the day represent a resounding, "Yes, I'm still here. What of it?"
Of course, it seems most wise for the city's bird population to start its sing-songing as the sun rises and not as gaggles of drunken buffoons flood out of divey watering holes. Chirping in the darkness is just a silly way to attract unwanted predators, correct? So why have I heard birds chirping as early as 2:30 in the morning when the only audible sounds should be police sirens and dudes puking their guts out in my side yard?
The same streetlights that guide your zigzagging steps home also dupe birds into believing it's time to rise and shine (there's a birdbrain joke to be had here, for sure). Light pollution is one culprit to thank for those restless early mornings when you just want to go to bed with a belly full of frozen pizza and Schlitz but can't because not only is the dreaded sunlight dangerously close to creeping through your shades, but the birds won't shut the fuck up.
Most of all, light pollution affects the timing of the dawn chorus, the burst of birdsong which occurs at the start of a new day, and the Max Planck study is the first investigate and document changes in breeding behaviour associated with it. "Our findings show clearly that light pollution influences the timing of breeding behaviour, with unknown consequences for bird populations," Dr. [Bart] Kempenaers said.
Looking at the effects of artificial lighting on dawn song in five common forest-breeding songbirds, it was found that in four of those five species, males near streetlights started singing significantly earlier in the morning than did males in other parts of the forest.
So not only is the city's nocturnal artificial glow secondhandedly disrupting your inebriated sleeping patterns, but it's also affecting the mating habits of songbirds, knocking them out of their biological rhythm. Mating is taking place at odd hours of the night/early morning, resulting in a lack of sleep and heightened susceptibility to being preyed upon—not terribly unlike what happens at your typical 4 AM bar.
Below is a nonurban take on the "dawn chorus":