While Williams realizes the investment potential of decoys, he does not make purchases for that reason. "I look for what I like," he said, adding that he focuses on local carvers—that is, Maryland-based artists.
Frank, of Howell, N.J., echoed the story. "I hunted and fished all of my life, and I loved the form of a decoy," he said. "I ultimately took one decoy out of my hunting rig, and that got me started with collecting."
A duck decoy sold in January at Sotheby's in New York for $767,000. It was a male eider created around 1900 by an unknown carver.
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"It's like anything else; you really have got to know what you're doing or get help from someone who knows what they're doing," said Nancy Druckman, head of American Folk Art for Sotheby's.
"There are infinite ways you can go wrong," she said, explaining that decoys can be fakes, the heads could have been replaced, or an uneducated buyer might overpay for an item.