Mexico’s Monarch Migration Survives Bout of Bad Weather (Nov 28-Dec 3, 2018)

Wind and rain whipped around our house on the night of November 28. I lay awake worrying about the butterflies, wondering how much worse the weather was 700 meters above us on Cerro Pelon. The shrill sounds outside brought to mind the devastation of March 9, 2016. That storm ripped trees out by their roots and threw frozen clusters of butterflies to the ground, killing some 37% of the colony.

I found myself bargaining with a higher power — please don’t kill them off just when the eastern monarch population is looking better than it has in years.

November 29 was rainy and miserable, and we told the Butterflies & Their People arborists to stay home for their own safety. Weather reports to the contrary, November 30 wasn’t any better, but Joel headed up the mountain with a stalwart group of visitors anyway, because for many it was their last day with us and thus their last chance to see monarchs. They found so many butterflies blown to the forest floor that they didn’t venture close; there was too much danger of stepping on stunned, torpid monarchs. At El Rosario that day, guides also cordoned off the main monarch area to protect butterflies blown to the forest floor.

Happily, skies cleared by December 1, and we headed up the mountain again with a group that included Monarch Watch Conservation Specialists Debbie Jackson and Diane Pruden along with Journey North reporter Estela Romero. There were still monarchs to be seen all over the understory, but they were shivering to warm themselves up and slowly making their way back up the trees.

Despite some signs of badly tattered wings, most of the monarchs managed to pick themselves up. Temperatures averaged 6 C/ 42.8 F throughout this bad weather event, so the wet butterflies did not freeze.
The three colonies we reported last week are still in residence, although the arborists note that the smaller, lower two seem to be joining the larger one in Paraje Beteta, whose trees now number well over 100. December 2 and 3 saw even more flight activity as skies stayed clear. As JM Butterfly B&B Guide Anayeli Moreno, who went to see the monarchs three days in a row, remarked, “I keep thinking it can’t get any better, and then it does.”
See also Week 3, Week 2, First of the Season Report, and Taking Care of the Forest in the Off Season.
