You could hear their raucous cries as they settled on our oak tree.
I remarked to my wife as I pointed to the tree. "Look at that flock of crows; there must be two dozen at least. 

My wife chuckled "That's not a flock, that's a murder of crows."

"Murder?" I asked. "Why do you call it murder?"

My wife looked at me and said: "Because that's the proper term for a crow gathering."

"No kidding?"

"No kidding."

I didn't dispute what she had to say; what disturbed me was that my wife just used a term that I wasn't familiar with. My wife is smarter than I am and I know it, but it still bothers me when she presents a factoid that I have absolutely no knowledge of. 

The next day, I visited my friend Harry. Harry was a former school administrator and a retired schoolteacher. He (other than my wife) is one of the smartest people that I know.
Harry and I conversed about all sorts of important stuff, like the weather and the state of the Internet. I finally pointed to a crow in a tree and asked him. "What do they call a group of crows?"

Harry shrugged his shoulders "Why a murder, of course."

"Huh?" I was sure that he was going to say a flock.

"Why do they call it a murder instead of a flock?"

Harry scratched his head. "Scientists still call it a flock, but poets and historians call a group of crows a murder. I am not completely sure about the origins, but I do have my theories. The term dates back to the 15^th century.  Bill, you need to understand that crows are scavengers. They are omnivorous and would just as well eat a human corpse as they would any other carrion. In the old days after a battle, many crows would gather. You could always tell where the dead were by the large numbers of crows. During the time of the black death in Europe, crows would be found wherever there were unburied bodies."

I replied. "Yeah Harry, but murder?" Crows didn't murder anyone."

"True," said Harry, "but in the old days, if a person were murdered and the body was dumped in a ditch somewhere, people might be alerted by flocks of crows."

I shook my head "Creepy."

I could tell that Harry enjoyed lecturing me. "Let me tell you some facts about crows. Crows and ravens are the stuff of legend; for centuries, they have been revered and reviled, fawned over and feared by humans. They are in the family Corvidae. That is the same family to which ravens, magpies, nutcrackers and jays belong.  Corvidae or Corvids are some of the most intelligent of all animals. These birds are every bit as smart as many of the great apes. They can be found on every continent with the exception of Antarctica.  A Corvid can both make and use tools. They also can communicate with each other and will often post sentries to warn other crows of danger.
Crows have wonderful memories. They can recognize people who have been good or mean to them. Not only can they recognize different people, but they can tell other crows to avoid or seek out these people as well. Crows will collect food and hide it to be eaten later. Crows will mate for life, they also have the ability to mimic other birds, and even people."

I looked at Harry. "I know that's true. A while back, my wife heard what she thought was a kitten in our big oak tree. She searched for a cat, but all she could see was a lone crow making meow noises. She thought that was funny, but really thought it strange when she heard "Here kitty kitty kitty" coming from the same crow. This was followed by "come here, come here…" It sounded like our neighbor calling her cats."

Harry shrugged "Amazing isn't it. I doubt if it knew what it was saying."

I shook my head. "Oh that crow knew what it was saying. It was teasing my neighbor's cats, and thoroughly enjoying itself in the process. Like you said crows are very intelligent and I think that they also have a sense of humor."

A few days later I was in our back yard with a couple of friends. One of our friends remarked that there seemed to be a whole flock of crows in our oak tree.

I laughed. "Flock of crows?" That's not a flock of crows, that's a murder."