It’s miller time.

Swarms of fluttering, dusty miller moths will zigzag across the Front Range for at least the next three weeks as they make their annual migration from Colorado’s southeastern plains in search of flowers. 

Whitney Cranshaw, a professor emeritus of entomology at Colorado State University, told The Gazette that drought and late freezes along the plains this spring meant fewer blooms, so the insects will soon invade gardens in the Colorado Springs and Denver metro areas to feed.

Colorado Springs parks system continues to fall in annual ranking

“When this happens, the moths can become highly concentrated in areas where there are blooms — such as irrigated landscapes around homes,” said Cranshaw, who called this “the oasis effect.”

Miller moths start out in alfalfa and wheat and other crops as an army cutworm. And then in late spring, they head to the Front Range where they hang around for several weeks enjoying 80 degree days and 50 degree nights. The next stop for the moths is mountains, where they invade until late summer before ending up back on the eastern plains to lay new eggs.

People often see the miller moth as a nuisance because they flutter around  lights and sometimes leave dark brown spots wherever they land. But Cranshaw said this type of moth does not feed or lay eggs once it finds itself in a home, and it does not eat clothing.

Bike park of converted junk opening in Colorado

To get rid of them, Cranshaw’s yearly moth guide suggests dimming all lights and even holding a light bulb over soapy water to attract them. They’ll fly toward the bulb and fall into the water. Cranshaw said sucking them into a vacuum also works well. Insecticides do not kill moths. In a YouTube video, Cranshaw advised jingling keys to attract them. 

Cranshaw, who made a career out of studying insects like the miller moth, said they are crucial for bird survival.

“Miller moths are large, high protein snack that come through just when birds need insects to raise their young,” Cranshaw said. “Plus, the moths often distract cats, which stalk and chase them and in doing so, may leave the birds alone.”

Waking dream: One-of-a-kind Colorado water park surprises on Western Slope

Grizzly bears in Yellowstone are also voracious moth eaters, finding them under rocks where they rest in large numbers.

Cranshaw said there won’t be nearly as many moths this season as there were in 1991 or 2002 when the statewide drought drove the moths west, where there were more blooms. In 2002, it seemed to city dwellers that the moths would never leave, as the season extended from April through early July.