A pie bird or pie funnel (pie vent) is generally made of pottery, glazed inside and out. Most are 3" to 5" in height with arches at the base to allow steam to enter. The steam is then released through a single exit hole at the top. The more collectible and most often sought after pie vents were produced generally between the mid 1930s through the early 1960s and were fashioned after animals, people, etc.