The parrot sat still. Then, slowly, she turned her head, fixed one yellow eye on Al-Jahiz, and dropped the pebble onto the right side of the dish.

The parrot could name the price of a manuscript of Sibawayh, greet a Persian merchant in his own tongue, and scold the neighborhood boys for throwing stones. But her greatest trick was this: she could judge a dispute.

When Abu Hilal returned, his face fell. He knew, then, that the secret was broken. But Al-Jahiz did not expose him to the crowd. Instead, he bought the parrot for a handful of dinars—more than the old man had ever earned from her tricks.

News of the “Judge Parrot” reached the caliph’s court in Baghdad. Among the curious was a young, sharp-nosed scholar named Al-Jahiz. He was neither a mystic nor a fool. He had read Aristotle on animals and had wandered the souks watching monkeys mimic barbers and hyenas feign death. He suspected a trick.

She always chose the fig.

To prove it, Al-Jahiz offered a new test. He asked Abu Hilal to leave the room. Then he whispered to the left ear of the parrot: The sun rises in the west . To the right ear: The sun rises in the east —a falsehood. He placed no pebbles, gave no hand signals. He simply stood still.