A Scotch crow.
There is a touching and authentic story about a bird that seemed to possess a number sense. A squire in Scotland became annoyed by a raucous crow that had made its nest in the watchtower of his estate, and he determined to shoot the bird. Repeatedly he tried to enter the tower to blast the bird, but each time at the man's approach the crow would leave its nest and take up a watchful position in a distant tree. When the wearied squire would finally leave the tower, the bird would return to its nest. Not wishing to be outsmarted by a bird-brain, the squire resorted to a ruse. He secured the assistance of a neighbor one day. The two men entered the tower, one man came out and went away, and the other remained within. But the crow was not deceived; it stayed in the distant tree until the man within the tower came out. The experiment now became a contest, and the next day three men entered the tower, two came out and went away, and the third waited within to blast the pesky bird. But the crow was not fooled; it remained in the distant tree until the man within the tower came out. The next day the experiment was repeated with four men, but still without success. Finally five men entered the tower, four came out and went away, and the fifth remained inside. At this point the crow seemed to have lost count and, unable to distinguish between four and five, it returned to its nest in the tower.
The conclusion of the story has not been recorded, but it is hoped that by the time of the final experiment a sufficient affection and respect had been built up for the crow so that the bird was allowed to remain nesting in the tower.