In the second week of December, the monarchs keep coming.

Ongoing Arrival and Colony Consolidation:

Cerro Pelon Chronicles: December 4–11, 2018

Temperatures started off warm at the beginning of the 2018 butterfly season. With midday averages at 13 C/55 F, Cerro Pelon’s monarchs were active every day from November 6th until the 28th. The same was true throughout the first three months of the 2017–18 season, and we were starting to wonder if warmer temps up at 10,000 feet was the new normal.

Butterflies & Their People Arborist Leonel documenting the arrival. The camera Leonel is using was purchased for the project by the Monarch Butterfly Fund. A second camera was donated by members of the International Butterfly Breeders Association. Leonel’s salary is paid by mulitiple supporters of a Go Fund Me campaign as well as contributions from former JM Butterfly B&B guests. Thank you to everyone who has made this sucessful forest protection project possible.

But since days of chilly drizzle struck during the last week of November, skies have been a bit moody and the temperatures decidedly lower. It almost looks like it could rain, but then it doesn’t.

Even though it’s now below 13 C on Cerro Pelon, the monarchs are still flying about, leading the arborists to believe the butterflies filling the sky are still in the process of arriving. The ever-growing girth of their colonies also suggests that this is the case. Strangely, until the Butterflies & Their People arborists started work last year, no one kept records of when the monarch arrival seemed to end each season. In 2017, the monarch colony kept growing with new arrivals until the third week of December. As for this season, we’ll let you know how things look next week.

In a recent update, we reported that three separate colonies had formed in the Carditos area of Cerro Pelon. On December 5th, the lower colony disappeared, merging with the higher two colonies, which continue to grow in size and density. One of these colonies continues in Paraje Beteta, while others have taken up residence 250 m. below the Paraje in an area called La Oyamel.

If you’ve seen the butterflies when they were on the Carditos side of Cerro Pelon, La Oyamel is right next to the barbed wire fence that divides Michoacán from the State of Mexico. In other words, as soon as you dismount from your horse as you end the ascent, you are now surrounded by trees draped in butterflies — while last week visitors had to hike 10–15 minutes to see this sight.

See also Week 4, Week 3, Week 2, Week 1, and Taking Care of the Forest in the Off Season.