When birds turn to thoughts of “love,” they don’t have a “bird-match.com” to turn to, so how do they find each other? Out in the wild, after all, there are significant sight barriers — trees, plants, hills and human structures. Even songbirds¹ perched in the same densely foliated tree may not be able to see each other. The solution, of course, is with sound.
A bird’s song sends a message: “I’m over here. I’m healthy — notice how pretty my song is and how strong my voice.” Drawn within sight of each other, birds can then do a visual assessment. It’s mostly males that sing, to attract females. But, females of some species, like the Northern Cardinal, also sing.
Birds tend to awaken before the sun does and may be singing as early as 4 a.m. They may sing any time, but early morning brings louder, livelier and more frequent songs. Scientists have a couple of theories about this. They call it the dawn chorus and speculate that birds sing then because light levels are too low to forage. Or that early, strong singing signals to other birds about the vitality and strength of the singers — they were healthy enough to survive the night.
Another theory is that early morning is when birds can best be heard, with no competition from other sources. Especially in cities, where the sounds of traffic, lawn mowers, and other power tools tend to drown them out later in the day.
Most songbirds sleep at night, but there are a few that sing when the sun goes down. American Robins sing into the night. Northern Whip-poor-wills, Northern Mockingbirds, and Nightingales sing at night.