Monarch population surges in Haliburton County
By Jenn Watt
Published July 31, 2018
By all accounts it’s been a banner year for monarch butterflies, the delicate, bright orange insects seen flitting around roadsides and open fields across the county.
For butterfly enthusiasts like Thom Lambert and Ed Poropat, this year’s abundance of monarchs has been a welcome sight.
“I enjoy seeing them like a lot of other people do. It’s lovely to see the numbers bouncing back,” said Poropat, who started the annual butterfly count for Haliburton County in 2000.
Each year a group of volunteers gets together and counts species and numbers of butterflies.
The numbers go up and down, but in recent years things hadn’t looked good for the monarchs. Last year, they counted 238.
This year 671 were counted.
“To put that in a bit more context, the count day weather was not ideal, with overall numbers of all other species quite low,” Lambert wrote in an email to the paper.
It’s the second highest monarch count in the last 18 years.
The highest was in 2012, when 768 were found.
The count was done July 14 this year. Lambert said volunteers travel in an area about 10 kilometres in any direction around Minden.
Data collected is sent to the North American Butterfly Association for their records.
Monarch butterflies migrate about 4,000 kilometres south to Mexico, where they overwinter before moving north again.
It takes several generations to make the trip north, with the butterflies stopping to lay eggs, which mature and continue the journey through the United States on their way to Canada.
A large population in Ontario isn’t just an indication of good local conditions. It also reflects the condition of the habitat the monarchs encountered and the weather patterns that helped or hindered their migration.
“There were a couple years there where it looked like the numbers were really rebounding quickly and things were looking great and then they had a bad storm right before the migration started and it wiped out millions of them,” Poropat said.
“Here we’re having a banner nice warm summer. There’s lots of milkweed around. They’re everywhere.”
However, despite the rebounding numbers this year, monarch populations are down in general and experts aren’t optimistic that numbers will ever fully recover.
Chip Taylor, director of Monarch Watch and professor emeritus, ecology and evolutionary biology at the University of Kansas, said there has been too much habitat loss.
Monarch numbers are estimated based on how many hectares they take up during their overwintering in Mexico.
“This year, we’re starting at an overwintering population of about 2.48 hectares,” Taylor said in a phone interview.
“And I’m predicting that the population will get back up to probably five hectares based on all the things I’m seeing and all the things I’m hearing.”
He said weather conditions have been more favourable than 2012 with warm weather greeting the tiny creatures as they make their way north.
“If you follow the dynamic here, it’s going to be really great in the midwest, it’s going to be great in most of Ontario, and it’s going to be a robust overwintering population if they get through the migration gauntlet, which is always a question.”
They will need plenty of nectar sources and favourable weather as they travel south, he said.
“If they’re migrating through a severe drought, that will take a toll. But right now the rains have been spotty enough here and there. It looks like fall flowering will be sufficient.”
Monarchs begin to leave Ontario in mid- to late-August.
Although there’s plenty of milkweed in Haliburton County for the caterpillars to feast upon, that’s not always the case – and the conditions need to be good throughout the migratory path in order to boost numbers.
Taylor said the number overwintering will give a good indication of how much milkweed was available through the American states.
“This is a very telling sort of thing. If we come out of this really extraordinary set of good conditions with only four-and-a-half hectares of butterflies, that’ll tell us milkweed is really down.”
Development eats up about a million acres a year of wilderness, he said.
Research has estimated that 1.4 billion milkweed stems would need to be re-established to bring the monarch population back.
And even if they could do that, Taylor cautions, climate change could throw all of those efforts out the window.
“We’re not on a good course climate wise. We’re really on a dangerous path in terms of sustaining all of the wildlife out there. Monarch butterflies are just a precursor to telling us that a lot of things are happening out there that we need to pay attention to.”
Poropat said the best place to find monarchs is in open fields or along roadsides.
Look for the milkweed plants and you’ll likely find them there.