Monarch perches on New England aster, Pelee Island, Ontario (Photo by NCC)
In Canada, monarchs exist primarily wherever milkweed and wildflowers such as goldenrod and asters exist. These plants grow in open spaces like the vast Tall Grass Prairie in Manitoba and on Ontario's Rice Lake Plains.
Monarchs that occur east of the Rocky Mountains, by far the largest population, arrive at 12 sites in the Transverse Neovolcanic Belt, a mountain range in central Mexico between early November and late December, and form large aggregations of millions of butterflies.
In March, the aggregrations begin to break up and begin their migration north in early April. They can travel almost 5,000 kilometres during their long, two-way migration.
Intriguingly, the monarch that returns to its northern habitat is often a generation or two removed from the monarch that started the migration. The migration of the North American monarch is a fascinating journey unlike any other butterfly in the world, which highlights the need for cooperation in species conservation across the continent.
What is this species' conservation status?
Environmental conditions and loss of breeding habitat pose threats to all monarchs and in Canada they are designated a species of special concern. The eastern population of the monarch is limited by loss of habitat, especially while wintering in Mexico. Development in Californian infringes on the wintering sites of the western population that overwinters in eucalyptus trees along the coast.
What is NCC doing to protect habitat for this species?
By protecting large open areas at the landscape scale, the Nature Conservancy of Canada (NCC) is helping monarchs and other species that depend on this type of habitat for their survival.
In Manitoba, Cathy Shaluk, education coordinator for NCC in the province, uses the monarch's migration to demonstrate the need for habitat conservation.
"In my presentations, I always talk about the survival mechanisms of monarchs and how they benefit the prairie ecosystems," says Cathy. "They feed on milkweed, a plant that many consider a weed and try to eradicate, but on the natural Manitoba Tall Grass Prairie Preserve, monarchs find a feast of milkweed."