Monarch butterflies face migration challenges as temperatures plummet

A sharp cool-down in Ontario raised concerns about how migrating monarch butterflies would fare. The Weather Network's Victoria Fenn Alvarado explains what you can do to help.

With a two-month journey of over 3,000 kilometres. Monarch butterflies typically migrate from southern Ontario to Mexico between the end of August and October, but the weather this fall has been making this annual task a challenging one.

Ontario experienced record-high temperatures at the beginning of October, but the sharp polar vortex that sank down earlier this week caused temperatures to plummet suddenly across southern Ontario. This is where Karin Davidson-Taylor, a butterfly expert at the Royal Botanical Gardens, says the concern lies with the monarchs.

“Being insects (and ectotherms), they need temperatures to be 15 degrees Celsius and above to be able to fly any distance and find food along the way," she explained. "There may be a lot of roosting (multiple butterflies clustering together in trees) happening during the cold snap.”

Davidson-Taylor is a trained and certified monarch handler, which is a legal requirement in Ontario (and regulated provincially) to capture, tag, and release these at-risk species.

Davidson-Taylor says the problem doesn't start or end with the temperature drop.

“The biggest threat is habitat loss,” she added.

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Monarchs stop often for food along their migratory journey, but unfortunately, that is hard for them to find.

"The most important thing you can do is create or restore habitat," Davidson-Taylor says. "In other words, think about where you can put some flowering plants that will support the food sources needed for the adults."

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Nectar is an adult monarch's main food source. By planting flowering plants, you can help the monarch’s migration journey. Host plants are also encouraged to be planted. These include milkweed species, the only plant that butterflies will lay their eggs on and the only plant the caterpillar eats. These are easy to find in Ontario, as there are 13 different kinds that can be found. The most common include common milkweed, swamp milkweed, and butterfly milkweed, according to Davidson-Taylor.

The importance of migration

Helping the monarch migrate is a win for other species, too.

Davidson Taylor explains that “you got to think about the big picture about the biodiversity within an area. And if you lose something, we may or may not know what the impact of losing that is. And so that's why if we can provide and support the habitat needs of monarchs, we're also supporting the habitat needs of lots of other animals.”

To learn more about the challenges facing monarch butterflies and what you can do to help, watch the video that precedes this article.

WATCH BELOW: Monarch caterpillar forms a cocoon before your eyes

(Header image courtesy of Letian D/Getty Images)