Cavansrack

In 1958, Mr. John Sellen had an idea. An avid field dog trainer, Mr. Sellen developed a training bumper made of canvas and packed with cork. Unmatched in its durability and scent holding qualities, many of Mr. Sellen's hunting colleagues took a liking to this "Canvasback Dummy" and wanted some for their own. So, Mr. Sellen took their orders, went home and began to manufacture the canvas dummies.

Source: Cavansrack online