The monarch butterfly is a wonderful creature and its population has decreased drastically over the last few years. Monarch butterflies cover thousand-mile journey from all over North America to alpine forests in central Mexico in late summer.

Three or four successive generations fly to breeding grounds, lay eggs and perish. The Monarchs that arrive in Canada in late summer are often fourth or fifth generation descendants of butterflies that flew south the previous year.

However, people are now witnessing a crisis in the survival of these species. Last year, for the first time in history, vast numbers of butterflies did not return to their Mexican forest. The population of eastern monarch was more than one billion in the mid-1990s.

In winter 2013, the population had dropped by more than 95% to 35 million, with a modest increase to 56.5 million this past winter.

According to Tyler Flockhart, postdoctoral research fellow of University of Guelph, a single severe storm could extinguish the entire monarch population. A snowstorm in 2002 wiped out 80 million butterflies.

A similar trend has been occurring west of the Rockies, where the western population overwinters in California and migrates as far north as central BC.

Monarch's caterpillars rely on milkweed as its sole food source. Milkweed plants contain small traces of cardenolides, bitter chemicals. These are stored by monarchs in their bodies to discourage predators. This phenomenon is called 'monophagy'.

However, eradication of its critical food source throughout much of its migration path by use of a glyphosate-based weed killer called Roundup has led to decline in its population.

Roundup is blanketed on the field, which kills plants like milkweed. As a result, several US Midwest states have lost most of their native milkweed and caused monarchs' reproductive rates to drop by more than 80%.

Gardeners throughout the country can take action to by planting milkweed and native nectar-producing plants in gardens, parks, community gardens, and in unused plots of land. This will create nurseries for Monarch larva.

The government has also proposed restrictions on use of herbicides and herbicides in gardens and along highways.