And if you’re going to go, this is the year to do it. Last week on Cerro Pelon, monarchs filled the skies with constant activity. We could see layer upon layer of monarchs circling overhead as far as the eye could see. Temperatures stayed warm, hovering around 12–13 C . The Butterflies and Their People arborists documented several instances of unseasonably early mating every

day. They also saw monarchs nectaring on the flowers that are thankfully already in bloom, especially on salvia mexicana. The colony we reported last week, in “Pareje Beteta,” swelled in numbers. Observers estimate that this area now hosts around 100 butterfly trees.

And then the colony started developing nearby satellites in the Carditos area, including one that formed in the afternoon of November 22 just above the clearing where guides had been parking visitors’ horses. The horse parking lot is now relocated to a lower clime, although you can still be dropped off in this clearing after the hour-plus ascent through switchbacks in what for the time being is still a moist and mossy forest (although there are already signs that the mud is giving way to dust). For the moment, the ride up takes about an hour, followed by a 10–15-minute ascent is on foot.

Then on November 24, the forest protectors discovered a third distinct colony. The rangers and arborists are working together in pairs to protect all three agglomerations, keeping visitors away from the smaller two, which are less accessible than the original colony.

In the daytime last week there were more monarchs in the sky than on the trees.

The Cerro Pelon protected area straddles two states and four ejidos (a political jurisdiction based on communally-held land). This season’s colonies are located on the State of Mexico side of the border. That side is home to a relatively intact forest of older, larger trees, thanks to 40 years of the regular presence of the State of Mexico-employed forest rangers. The rangers, like the arborists, are unarmed. They don’t even have the authority to fine people caught cutting trees. But their very presence worked as a deterrent. Meanwhile, the Michoacán side of the sanctuary, which was outside of their jurisdiction, is badly deforested. Three of the four B&TP arborists are from Michoacán communities. Already in the past year that they started riding to work along Cerro Pelon’s Michoacán trails, clandestine logging in the sanctuary’s core has declined dramatically.

Retired forest ranger Melquiades Moreno visited the colonies on Sunday, November 25. He was surprised to see how low the monarchs were roosting so early in the season. In years past, November saw them up around 3,200 m. (The peak of Cerro Pelon reaches 3510 m.) But the current colonies are already roosting at 3,100 meters above sea level.

My husband Joel was with his dad that day. He called me from the colony, absolutely ecstatic about the spectacle. Joel has taken people to see the monarchs about 700 times over the course of the last seven seasons, so that’s