Species at risk: The monarch butterfly (danaus plexippus)

A monarch butterfly

Photo: A monarch butterfly


Karen Abel

Environment, Natural heritage

Published Date: May 10, 2007

The beautiful Monarch butterfly is the most recognized butterfly in North America. What is not commonly known is that it is also a species at risk in Canada. Perhaps even lesser known is the monumental journey it makes twice a year. A mystery until recently, the migration of the Monarch is a fascinating story of survival and interdependency.

Each spring, the Monarch butterfly arrives in Ontario from as far south as Mexico – a 3,000 km (1,864 miles) journey! Throughout the summer, they search for milkweed plants where they lay eggs to produce new generations of Monarchs. In autumn, the migration begins again with millions of Monarchs making an exodus to their winter roosting grounds in Mexico’s volcanic mountains. They can be seen preparing for their arduous journey each fall – feeding on nectar from native wildflowers such as asters and goldenrods. Challenged by storms, cars and large bodies of water, few monarchs survive the complete journey. Along the way, eggs are laid on milkweeds to ensure many more generations of monarchs will continue the flight south.

Designated as a species of “Special concern” provincially and nationally, the survival of the Monarch butterfly is dependent on milkweed plants. Commonly growing in meadows and along roadsides, the milkweed is the sole food source for Monarch caterpillars. In Ontario, the survival of the Monarch is threatened by the widespread use of herbicides and pesticides. You can help protect the Monarch and aid its incredible migration by planting milkweeds and nectar-producing wildflowers in your garden.