Mexico City: Embattled monarch butterflies faced an extra hurdle in this year’s migration; torrential winds and rain cause by Hurricane Patricia which crashed into Mexico on Friday.

As a result, the monarchs, unique among butterflies for the regularity and breadth of their annual migration, diverted from their usual route and found refuge in ravines in Nuevo Leon state in northern Mexico, conservation authorities said on Monday.

Patricia, one of the most powerful storms on record packing 266km/h winds, carved a swathe through relatively remote parts of rural Mexico last week.

“When they started to feel the humidity from the west, the push from the Pacific with the wind and humidity from Patricia, the Monarchs moved their route east,” Gloria Tavera, a regional head of the National Commission for Natural Protected Areas (Conanp), said.

Tavera added that the butterflies, which migrate thousands of kilometres from Mexico, across the United States to Canada, and then back again, will take up their usual route again when the climate returns to normal.

Monarch populations are estimated to have fallen by as much as 80 per cent in the past two decades because of destruction of milkweed plants they depend on to lay their eggs and nourish hatching larvae, according to the Xerces Society for Invertebrate Conservation.