Pugnacity in birds

It has started up again. Early in the morning there is a thump, thump, thump from the window above

It has started up again. Early in the morning there is a thump, thump, thump from the window above. It's that blackbird doing what the experts call image-fighting. It goes on until you go out and wave it off. A chance turning up of a small paperback printed 30 years ago (The Countryman Wild Life Book) shows that it takes many forms: on hub-caps, for instance, which 30 years ago must have been very reflective, shiny polished things. One morning, finding the hub-cap smeared with red, the owner feared the worst, but was soon surprised to find the bird returning with a morello cherry in his beak, evidently trying to feed his alter ego in the reflection. One woman wrote of the most persistent case surely on record: "In April 1963 I first noticed a male house sparrow banging against a bedroom window of my neighbour's house. It kept up its attacks from early morning until late evening except when, at my suggestion, the curtains were drawn." (One might ask, what was left of the poor bird's beak?) "But it went on, sometimes at another of the windows but, with a break of five or six weeks in the autumn, it continued its visits until the following June. Then it disappeared, coming back at the end of March this year to the same window. It kept up its attacks for a month before vanishing again."

A bird described as a bookmerie shrike attacked a workshop window in East London, South Africa, until if so fouled the glass that no reflection could be seen. One small bird attacked a window so often and so fiercely that it was found dead underneath it. "And the habit is not confined to the smaller birds. One pair of crows attacked the French window of a house near Cardiff, rapped sharply on the glass several times (and they have heavy beaks), then flew up and scratched the pane with their craws. On the ledge, they set to fighting each other; feathers flew and the window became smeared with dirt and drops of blood. The pattern changed. The crows would perch on a branch about 20 yards from the window, then launch themselves together, both striking on the pane." With a good bang. "Then dropping to the ground to fight each other." Could all this be a form of overcoming boredom?