Those owls are probably declaring territorial rights.

My dog does spend a great deal of the day sleeping, but he's too lazy to chase mice and squirrels. I know that's a pretty astonishing degree of laziness, but it's true. I think it's because the vet snipped off his little jewels when he was young that he is so lacking in initiative. The only thing that really moves him is food.

Perhaps the same would be true of the vet if the same operation had been done on him early in life...