While official data are still being collected, the outlook is grim, experts said.
"Normally, at this time of year, I'd see hundreds," Joe Derek, former naturalist for the City of Farmington Hills, told the Detroit Free Press. "In my life, I've never seen a season where we're not seeing butterflies really of any kind."
Holli Ward, executive director of the Michigan Butterflies Project, says she has seen very few monarchs, the type she studies most, this year.
"We go out and are looking, looking, inspecting thoroughly," she says. "On a good day, we're looking at hundreds of milkweed stalks -- every week, twice a week since early June. We have not seen a single egg or caterpillar."
Part of the problem, experts said, is development of prairies and grasslands, eliminating native on plants on huge swaths of habitat that used to lure and feed the delicate insects.
That means fewer butterflies will be seen in the nation's gardens, Jeffrey Glassberg, president of the North American Butterfly Association, said.
"Every time someone takes a meadow and turns it into a parking lot, they are removing large numbers of butterflies from North America," he said. "And that happens, of course, every single day."
Weather has been a factor too, experts said.
"This year's cooler, wetter spring really didn't help," Ward said. "Couple that with last year's extremely hot, extremely dry weather, and it's a terrible situation for monarchs."