A high-pitched, piercing cry is a shriek. A common response to finding a snake curled in the silverware drawer would be to shriek.
You can shriek in fear, surprise, or even shriek with laughter. If the sound you make is high, sharp, and loud, it's a shriek. A teenager who sees her favorite movie star might shriek, "Look who it is!" And, little kids in an inflatable bouncy house will very likely shriek with delight. The word shriek sounds very much like what it means, and its Old Norse root skrækja, "to screech," may have originated for that very reason.