Harbingers of Spring: The Mighty Monarch Returns

Do you remember learning the life cycle of the butterfly when you were in grade school science? Metamorphosis takes place when an egg changes into larvae (a caterpillar), and then a pupa, or chrysalis, forms. Finally, out from the chrysalis into the world—where it will only live a few weeks—at last emerges a beautiful butterfly.

With the exception perhaps of the honeybee, there may be no other insect as iconic as the butterfly. They have evolved to represent emblems of positivity, rejuvenation and, particularly at this time of year, a reassuring sign that a warmer season is underway. It must be spring, after all, if we glimpse the chaotic flutter of a brightly-coloured monarch butterfly.

Whether you are 7 or 77, the transformation that these graceful creatures undergo is both fascinating and mysterious. There are so many things that even researchers have yet to discover about these flying insects, including those living among us in Southern Ontario.

Scientists do know that the migration of the orange and black monarch butterfly is unlike any other. Called by the leading edge of colder air in November, monarchs set out on a journey spanning over 3000 km south to Mexico for the winter. The trip takes an average of 45 days, with some of the winged wonders travelling more than 80 km each day.

The great mystery here is that no monarch making the trip has ever traveled the route before, yet they instinctively know where to go. The monarchs returning to Canada each spring are not the same as those that began the migration in the autumn. After basking in the tropical Mexican sun, monarchs begin a generational process that ensures the species return to their Canadian summer home. As they leave the winter sites in early April, these older butterflies lay eggs in parts of the southern United States and their descendants are the ones that fly north, crossing international borders to be discovered and admired by Canadians in early June. Scientists believe the secret of their navigational prowess may lie in an internal compass calibrated to the position of the sun at different times of year.

In the summer and early fall, monarchs move from flower to flower, feasting on nectar. In mid-fall, they travel in large numbers near the shores of Lake Erie and Lake Ontario, where they cluster together on trees to form roosts (overnight resting areas) before crossing the lakes. These areas may contain a few hundred to several thousand monarchs. They typically form clusters in the same areas year after year.

Naturally, monarch populations will vary from winter storm deaths, poor breeding conditions, predators and other pressures. But now, despite their innate inter-generational survival techniques, researchers have noted alarming changes in both the Eastern and Western populations of monarch butterflies, with an 80 percent decline in just 20 years, largely due to habitat loss. Conservationists are concerned that the monarch population could become too low to sustain itself. As a result, the monarch butterfly is identified as a species of Special Concern by both the provincial and federal governments. This means the species could be at risk of becoming threatened or endangered if we don’t take steps to protect it.

In Ontario, there are more than 100 different species of butterflies, just a small portion of the nearly 20,000 different types worldwide. To help support their survival, conservation experts are building more butterfly and pollinator gardens, which offer crucial feeding habitats for butterflies, and encouraging gardeners to include more butterfly-friendly flowers and plants in their home gardens (see our sidebar, Pollinator Paradise at Riverwood Conservancy!)

Some of these efforts may be paying off—more monarchs were counted making the annual pilgrimage last year. To learn more about these amazing creatures and their efforts to survive, join me for a new episode of my Big Blue Marble Podcast: The BounceBack Of The Butterfly.


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