why do northern mockingbirds sing at night
Mockingbirds have a very distinct song that they sing. They are often recognizable right away in the spring and their song seems to become stronger as the summer days get longer. However, mockingbirds donвt just sing during the day. They sing all night as well. For hours upon hours you can enjoy the song of the mockingbird all summer long if you really want to. But why do mockingbirds sing at night, and why are they singing for so much longer than other birds? Mainly the male mockingbird is attempting to attract a mate. While this is done mostly during the daytime hours, their songs continue throughout the night. Simply put, the mockingbirds are attempting to fend off other suitors.
They seem to think that they are in a constant battle with other mockingbirds over their territory as well as their mates. The more threatened a mockingbird feels, the louder their song becomes. So if you are listening at night and hear a mockingbird that seems to be getting louder and more aggressive with their song itвs because they are trying to fight off either a real or imaginary threat with other mockingbirds.
I had been working late one night in July, and at around 2 a. m. it suddenly occurred to me that Jack, as I called the male of the family, was becoming rather obnoxious. He had been singing without pause for at least an hour, and as the night wore on, his volume was rising.
Maybe because the background noise was quieter his voice just seemed louder, but the fact was, my ears were actually fluttering with the sharp, choppy, ragged phrases that mockingbirds like. But why was he singing at night in the first place, when most species of birds simply sleep? It was hard to make biological sense of it. For one thing, he was giving away his position to every cat on the block. Second, all that volume was generated by the laborious convulsions of Jack's diaphragm and breast muscles, and the work took energy. Birds the size of Jack sometimes eat twice their body weight each day to pay the cost for warm blood, and, on top of the usual worries of survival, Jack and his mate, Jill, were rearing some very hungry chicks.
Jack and Jill were locked into the frantic pursuit of energy, which is what life amounts to, and here he was blaring forth all night long. No bird would spend that kind of energy unless it was critically important. "I wonder," I thought, "if this racket drives cats away? " It was plausible. But no--it couldn't be a defense because if that were so, all birds would have hit upon the secret and would be singing at night. The din would be stupefying. No--the only reason I could see had to be competition with other mockingbirds. And that would be easy to test.
I set a tape recorder in the window and began recording. Half an hour later Jack stopped for a breather, maybe even a nap. Not, however, if I could help it. I rewound the tape and turned the volume up. "Chireep, chireep," went the tape. " Chireep! Chireep! " erupted Jack not a second later. "Rash, rash, rash," went the tape. " Rash! Rash! Rash! " screamed Jack. "Tweedle, tweedle, tweedle. " " Tweedle! Tweedle! Tweedle! " gurgled Jack, almost strangling in frustration. He was reacting not only to a recording of a song he had sung no more than 30 minutes earlier but also to each phrase. In his little bird's brain, he was being challenged by a monster stud, and by the gods and the bushes and the bugs, he was not going to go quietly.
The evidence clearly suggested the kind of life a mockingbird lives. Like most songbirds, they have evolved a system of parceling up the land, which acts as a kind of natural farm, with the males defending the boundaries. They rarely fight physically, though, presumably because injury is too costly at a time when a bird needs all its strength just to break even in the energy economics of life. But there is usually no need to fight, because the vigor and skill of your song gives a good idea of the vigor and skill of your body--should a little more convincing be necessary.
- Autor: esagecys
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