Funnel-style steam vents have been placed in the center of fruit and meat pies during cooking since Victorian times; bird shapes came later.^[1]

Pie funnels were used to prevent pie filling from boiling up and leaking through the crust by allowing steam to escape from inside the pie.^[2] They also supported the pastry crust in the center of the pie, so that it did not sag in the middle, and are occasionally known as "crustholders". Older ovens had more problems with uniform heating, and the pie bird prevented boil-over in pie cooking.

The traditional inverted funnels, with arches on the bottom for steam to enter, were followed by ceramic birds; and from the 1940s they have been produced in a multitude of designs.^[1] This trend has been particularly noticeable in recent times, due to their increasing popularity as gifts and collectors' items rather than simply utilitarian kitchen tools.