Lack of snow threatens endangered Manitoba butterfly

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This year, just 36 were observed in the province.

To survive the winter, the insect relies on a blanket of snow for insulation.

"We know they don't go into the ground. They don't spin themselves into any kind of protective cocoon or anything. The larvae, we think, just hang out in the leaf litter and really, theironly protection from the cold would be the snow," said Hamel.

"And so without that snow protection, again, researchers are a bit nervous when 30 temperatures come.We could be losing some of those caterpillars, and every one of them matters at this point."

The butterfly is a pollinator and an important part of a healthy ecosystem, Hamel said.

It's a mystery to researchers why populations are shrinking.

Fewer than 500 were observed this year in North America. A zoo in Minnesota is studying it in captivity to better understand its life cycle and how it survives the winter.

Researchers cannot actively go out and check on them in the winter months.

"We actually don't even want to walk in the sites where they're remaining, because we don't even want to accidentally step on one. It's just such on a brink of collapse that we don't want to be responsible ourselves for any additional mortality."

Another concern with the warm temperatures is that the insects are coming out of hibernation prematurely, Hamelsaid.

"Presumably the caterpillars are waking up a little bit. They're probably burning some of their fat reserves, and they need that to get through to the spring."

The state of this species is concerning on a wider scale, he said.

"Many, many species that depend on the prairie [grasslands] are declining rapidly certain kinds of grasslands birds, many other butterflies and moss species," he said.

"The driver in that is likely the tremendous loss of habitat over the last century."