Thousands of “straggler” monarch butterflies may be stranded in Canada

monarch butterfly on fall leaves [Credit: Billings Brett, USFWS]

At this time of year, most monarch butterflies are in Texas. Each year, monarchs migrate 3000 miles from North America to Mexico, where they spend the winter. However, this year, many monarchs are still being seen in Canada and need to get out of town if they hope to survive.

“They’re running out of time,” Darlene Burgess told the CBC. Burgess does monarch counts at Point Pelee National Park in Ontario and has been seeing many more monarchs than is usual for this time of year.

Scientists like Elizabeth Howard, director of the monarch-tracking organization Journey North, believe the monarchs have been left behind for a few reasons, one of which is the unseasonably warm weather. The long-lasting summer is believed to have led to an extra generation of the butterflies, who haven’t begun the migration yet because they were born late. Strong winds from the south have also been discouraging butterflies from leaving,

Now, however, temperatures are dropping, and the butterflies may find themselves stuck. They are unable to fly in cold weather, and even if they manage to avoid freezing, their food sources will soon be gone.

Monarch populations have been dwindling in recent years, and their food sources, particularly milkweed, have become less available. Some have been petitioning for them to be categorized as a threatened species.

Biologist Karen Oberhauser of the University of Wisconsin says that the whole situation is an “ominous” sign of climate change, but that some of the butterflies currently stranded  will still manage to make it to Mexico.

As Howard puts it, “What’s really important is they’ve got to get out of town.”

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