The bird that sings in the dark is the one that keeps you awake at night if it sings its heart out while perched in the tree by your bedroom window. Probably, this is a northern nightingale. If it’s one of those, you’ll know it because it doesn’t sing a single tune like most other birds. It will repeat a melody five or even ten times, but then it will go to another. For the most part, these are the songs of other birds that it emulates. On occasion, it will use its vocal cords to repeat a non-bird sound. The popular film series titled “The Hunger Games” features a fictional bird called the Mockingjay, which repeats human sounds, including the characteristic whistle of Katniss Everdeen, the main character.
You may not be aware that your nocturnal singer is always a male, and only a male with no partner. Perhaps this explains the matter, this bird will sing to the female mockingbirds throughout the night, intending to bring one of them to mate with it just to shut it up. Ok, I made it up. However, it is true that once mated, the singer will no longer sing at night. He will sing during the day. The qualities of the inhabitants of the natural world often have a logic behind them. So why would the single nightingale imitate the songs of other birds?
No one knows for sure, but there are three plausible explanations. The first is that other bird species will shut up when they hear your song in a way that confuses them. If that’s true, the male mockingbird will have a kind of stage, on which to perform a solo performance. The second possibility is that the bird, like most animals, is territorial. Somehow, it is recognized that the bird that can sing the most songs is the dominant bird in the northern nightingale species. Therefore, the less dominant single male mockingbirds will fly out of the area. I know this bird adds more songs over time, so the one who knows the most songs is the oldest bird. Probably the third reason is the most plausible. A female mockingbird may be more turned on by “the smartest bird in the room,” so to speak, the one who knows more songs than the other single birds.