Why are the birds so loud, so early in the morning?

CHICAGO — If you've ever been up before the sun, you may have been surprised to hear the sound of birds already awake and chirping outside your window.

According to WGN reporter (and our first Ask WGN questioner) Tonya Francisco, even when she wakes up in the middle of the night with her infant daughter Lexi, their calls seem especially loud and annoying.

"I'll give her a bottle and we're sitting in a rocking chair, and we're both trying to fall asleep and you'll hear this bird... chirping and chirping and chirping," Tonya says. "I'm like, it's four-something in the morning, what do you have to chat about?"

So, Tonya asks: Why are the birds so loud, so early in the morning?

This "dawn chorus" of birds typically starts about half an hour before sunrise, and carries on until about thirty minutes after the sun is up. During this time, birds actually do sing louder and more frequent than the rest of the day.

One theory is that since there isn't enough light to go foraging for food, they spend the time singing instead, according to Mark Luscombe, President of the Illinois Audubon Society's Fort Dearborn Chapter. There's also less competition and less interfering noise, which makes it easier to distinguish individual songs. Either way, most of the birds you hear early in the morning are males.

"They often have a defined territory they're trying to keep other males out of, or maybe a group of females flew in during the night and they're trying to convince that female that they're the most virile male in the area and the most likely to produce wonderful offspring," Luscombe said.

Only about 40 percent of the 750 North American species of birds are considered “song birds,” Luscombe said. Some song birds have only one song while others, such as the Northern Mockingbird, can have as many as 300. While each species often has their particular song, there can be minor variations that identify particular individuals.

City lights may make the dawn chorus start earlier

While the dawn chorus usually begins just before sunrise, it seems to start even earlier in cities. Recent research has shown that artificial light is having a significant effect on birds, according to the Illinois Audubon Society's Jim Herkert. Whether from streetlights, buildings or other sources, it seems to artificial light causes the dawn chorus to begin earlier than in rural areas. Cloud cover and mist seem to amplify the effect even more by trapping light and making the night brighter.

Robins are usually among the first to start the dawn chorus, and seem to be particularly affected by artificial light. Herkert said a study out east found urban robins started singing as early as an hour after midnight. According to Mark Luscombe, robins are often the source of complaints related to bird calls early in the morning.

Here's what a robin call sounds like:

Tonya captured a video of the birds that she heard from outside the window of her Bronzeville home. After listening to the video, Mark identified the culprit as none other than the very same North American Robin.

"You've probably heard the saying, ' the early bird catches the worm?' That's the robin," Luscombe said.

While there isn't much you can do about bird noise (other than get a white noise machine, like Tonya did), there is one bright spot. Bird song usually hits its peak during nesting season, which began at the end of winter and is just winding down. So while the birds will likely keep chirping early in the morning, they are probably going to turn the volume down very soon.

Do you have something you've always wondered about the people, places or things happening in your community? You can Ask WGN at wgntv.com/ask.