MINNEAPOLIS (AP) - Gardeners are noticing a scarcity of colorful monarch butterflies in the Twin Cities this year.

At the University of Minnesota's Bell Museum, the wildlife hot line has been peppered with "Where are the monarchs?" calls.

Usually dozens of monarchs flit in prairie areas north of the Twin Cities, but observers report seeing only a few this year.

Experts say the monarchs' low numbers aren't caused by the butterflies' shrinking winter habitat in Mexico, but by cold, wet springs in Minnesota and in Texas and Oklahoma. Minnesota's recent extremely dry weather hasn't helped, either.

Chip Taylor, founder of the group Monarch Watch, says not to worry. Taylor, a professor and insect ecologist at the University of Kansas, says monarchs are a species "that deals with adversity quite well, and the population can rebound very quickly."

Karen Oberhauser, an associate professor at the University of Minnesota, runs the Monarch Larva Monitoring Project that relies on volunteers to submit monarch data from all over the country. She says population reports from the Upper Midwest are running below average.

"I just talked to a volunteer in North Dakota who has a prairie filled with beautiful milkweed," Oberhauser said. "In a normal year, she sees dozens of monarchs. This year, she's seen one egg and three larvae."

Taylor said the problems started earlier this year, when a fat and healthy crop of monarchs left Mexico in March to begin their migration north. Exceptionally cold weather hit Texas and the Southwest through the first half of June, just as the first new generation of monarchs was beginning to migrate. Those butterflies typically mature in April and fly all the way to Minnesota and even Canada over a six-week period.

But they don't fly in rain and cold, and they can't thrive if the plants they rely on for nectar aren't at the right stage of development.

"I think relatively few reproductive monarchs reached the northern parts of the range," Taylor said.

Oberhauser said she saw three monarchs in her big perennial garden in Roseville last week. But she cautions that individual observations can be misleading.

"Gardens are just a fragment of habitat, and there may be some years when monarchs just don't find a garden," she said.

Oberhauser will analyze data from her monarch count in September.