Point Pelee National Park in Leamington, Ont., has cancelled its annual monarch butterfly count due to the lack of butterflies.

The annual monarch migration is one of the park's signature events.

The southern tip of Canada is a critical stopover for the migrating butterflies while they make their 3,000-kilometre journey to the mountains of central Mexico.

Clusters of monarchs are typically found keeping warm in tree tops as they prepare for flight across Lake Erie. Hundreds can normally be seen flying across over the water every hour.

Not this year.

“We’re seeing a few, but certainly not seeing the number we’re accustomed to,” interpretation co-ordinator  Sarah Rupert said. “From what we’re hearing from other places, that’s kind of the trend across Ontario.”

Elizabeth Howard, the director and founder of Journey North, an organization that tracks the monarch migration, told CBC News earlier this week that numbers are down across North America, not just in southern Ontario.

"During migration, monarchs form overnight roosts in places like Point Pelee or Long Point [in southern Ontario], where the monarchs are congregating before crossing the Great Lakes, places where people generally see huge overnight clusters of monarchs gathering,” she said.

Howard told CBC News that at this time in 2011, Journey North had already received 55 reports of roosts, followed by just 25 in 2012. This year, only 17 reports of roosts came in.

Rupert said clustering “is the experience people are hoping to have when they come to Point Pelee.”

Because of the lack of monarchs, the park has focused heavily on its live monarch exhibit, which raises monarchs from caterpillar to butterfly.

Rupert tagged and released six Tuesday. Two more were to be released Wednesday. Another three are going to take flight next week.

“When we tag our butterflies we send the numbers to Monarch Watch. They’re able to track migration routes and see what’s going on, on other routes,” Rupert said.

Monarch Watch is a co-operative network of students, teachers, volunteers and researchers dedicated to the study of the monarch butterfly.

“Even visitors coming into the park say they haven’t seen as many monarchs in their yards,” Rupert said. “They just aren’t seeing the numbers.”

Scientists stress the loss of monarch habitat needs to be reversed.

Chip Taylor of Monarch Watch says that "in the Midwest, we're seeing a tremendous loss of habitat due to the type of agriculture that's been adopted here, [like] Roundup-ready corn and soybeans, which has taken the milkweeds out of those row crops. We're seeing overzealous management of roadside marshes, excessive use of herbicides here and there."

Monarch Watch and Journey North are trying to promote monarch habitat restoration by planting milkweeds, which is the main food source for monarch larvae.

“This time of year, flowering plants are needed.  I can’t emphasize that enough,” Rupert said.