In a simple world, I just wanted to play with shriekers and sensors but I realised that a manualy placed shrieker does not call the Warden. Even if I try a lot more times, it is not working. I can't give a screenshot but I can telle you how you can do it. Just go to creative inventory and take a shrieker. Place it down and activate it 3 or 4 times. The Warden will not respond in the daylight and even in the night or in an Ancient City, he will not respond or spawn. But a shrieker that naturaly appeared in Ancient Cities will call him.

Please do something for the next version.