Matt Downs floated a perfect analogy for a decoy show.

“I look at this sort of like going to those ‘Star Trek’ conventions,’’ he said. ‘‘I understand it is weird, but I really don’t want to stop doing it.’’

Take the North American Vintage Decoy and Sporting Collectibles Show, which runs April 25-29 at the Westin Lombard Chicago Hotel. It’s billed as ‘‘the largest decoy and sporting collectibles show in North America’’ and is hosted by the North American Decoy Collectors Association.

When I attended earlier incarnations at the former Pheasant Run Resort, it overwhelmed me as a casual fan.

Apparently, I missed the coolest part — room-to-room trading, which is the first three days. I intend to correct that this year.

‘‘Most of the dealers are there starting Monday or Tuesday,’’ Downs said. ‘‘A lot of the good stuff disappears in the room-to-room trading.’’

The Guyette and Deeter Inc. auction is the third and fourth days. The ballroom show is the fourth and fifth days. Events are open to the public.

‘‘Room-to-room is probably the most fun,’’ Downs said. ‘‘New people probably have the most fun and are the most social. At Pheasant Run, it would be the entire building. It would take half the day to walk through, and you would forget what you room you saw something you wanted. There were any manner of things. Some were insanely expensive and the next room at a [bargain price].’’

Decoy collection is wildly diverse.

‘‘Different people are drawn to different things,’’ Downs said. ‘‘Some are into history: Who made decoys for this gun club? Other people buy based on what looks cool to them. Some focus on factory decoys; some of those are more affordable.’’

There are guys from rural areas who have hunted and fished all their lives, with limited money, who spend what they can. Then you have major collectors, such as Paul Tudor Jones.

‘‘You have this widespread [gathering],’’ Downs said. ‘‘Some have their own art advisers come with them.’’

I wondered whether people ever use collected decoys.

‘‘There are people who will throw them out in their rigs,’’ Downs said.

He cited a top carver, Marty Hanson of Hayward, Wisconsin. People use his decoys, which are worth thousands. Michigan collector Ken Cole hunts over his collected decoys.

Cameron McIntyre of Virginia is an ‘‘exceptional carver’’ who uses hand tools. He’s so talented that he restores old decoys. He’s an all-round artist of note.

‘‘At the show, they are celebrities and they are rock stars,’’ Downs said.

As for himself, Downs said: ‘‘I carve as a hobby. I don’t really tell anyone about it. It doesn’t make sense to people.’’

At the auction, before the market crash, sales regularly set world records and routinely reached hundreds of thousands of dollars. The market has settled since then.

Mike Stevenson of Guyette & Deeter emailed: ‘‘A black duck by the Caines brothers is the top lot in the sale, estimated at $150,000 to $180,000.’’

He mentioned a couple of other highlights: ‘‘The George & Miriam Van Walleghem collection (the most important fish-decoy collection to come to auction and many exciting duck decoys) and the Herb Desch collection (the finest selection of Wisconsin decoys ever offered in a single sale).’’

The show will feature vintage displays, demonstrations of contemporary carving and painting and free appraisals.

‘‘There’s something for everyone,’’ Downs said. ‘‘You can buy things for $10. You don’t have to buy anything. You can spend thousands of dollars if you want to.’’

Adult admission is $5. For more information, call (586) 530-6586 or go to nadecoycollectors.org.