It's how jays protect each other as they move about neighborhood yards in family groups of maybe a half-dozen searching for food. One or two jays perch in a tree as lookouts. If the lookouts spot a cat, they'll yell with jeer calls, and then the whole family erupts in jeers.

Why do blue jays squawk?

Next time you hear blue jays making a fuss, remember this phrase: “When jays are squawking, something's walking.” Blue jays consider deer to be intruders, and they often follow them just like they will a cat or other predator.

Why do jays screech?

The screaming call usually lets you know a jay is nearby and it is usually given when a bird is on the move, so watch for a bird flying between the trees with its distinctive flash of white on the rump.