By Jim McCausland, Sunset Magazine
Long ago, well beyond the reach of the statute of limitations, a friend of mine shot a crow whose gang was vandalizing the vegetable garden behind his barn. From that day, every time he walked from the house to the barn, the crows withdrew to the treetops around his field and cawed at him.
This made my friend, a math teacher, wonder how bright crows really are. He asked his son to walk with him from the house to the barn. The crows flew off. He sent his son back to the house alone. The crows stayed away. It was clear to the birds that if two went into the barn and one came out, somebody was still inside with the shotgun.
The next day he took his two sons to the barn with him, and again the crows flew off. He went back to the house with one of the boys, but the crows stayed away. They knew that three less two equaled one trigger-man left behind.
The following day he took his two sons and his daughter out to the barn, and off flew his nemeses. He returned to the house with two others, but the crows stayed away.
The next morning his wife joined the gang, but when only four exited the barn the crows knew that not everybody had left.
Finally he called a neighbor to come over and join the daily trek. All six people entered the barn, five returned to the house—and the crows returned to the vegetable patch.
They can do subtraction up to five, my friend surmised, but not six. Judging from all the crows in the neighborhood, that's all the math you need to be a successful crow.
