Large Colonies

Estela Romero and Ellen Sharp provide updates from the Monarch Butterfly Biosphere Reserve in Mexico. Gail Morris shares more good news from overwintering sites in California and highlights monarch activity in Arizona. Plus, a special invitation to report winter monarch sightings in the Southeastern U.S.

overwintering monarchs — Colonies of monarchs are growing in size as the overwintering season continues. Photo by: Estela Romero

Letter from Estela Romero: Largest Colonies Observed in El Rosario Sanctuary

At El Rosario Sanctuary, Estela Romero highlights a large monarch colony at a site that usually only sees monarchs later in the season. Estela writes, "At the time of this reporting, monarchs in El Rosario Sanctuary occupy three different sites. Early in December, Los Orcones and Los Letreros colonies were very active and large; now they are much smaller. Just a few hundred meters north, a colony has formed that is dense and concentrated. A beautiful mass of stunning monarch butterflies can be seen in the Oyamal fir trees. It is only mid-December, yet monarchs are settled at Las Arenitas colony, a site they usually move to in February."

Leer más de la carta de Estela Romero: (versión en Español)» El Rosario, Ininterrumpidamente La Colonia en Hibernación más Grande en México»

Letter from Ellen Sharp: Colonies Consolidating Into One

At Cerro Pelon Sanctuary, Ellen Sharp provides an update on monarch movement and details the latest content from the Adopt a Colony project. Ellen writes, "I haven’t visited the monarch butterfly colony for a while, but Ranger Pato sends these observations from the mountain: what started off as three separate colonies is now consolidating into a large one in El Capulin on the Michoacan side of the sanctuary. Butterflies cover an estimated 125 trees . . . We’re especially pleased with our latest featured video, a reenactment of visiting the El Capulin colony with her mother, my mother-in-law, Rosa. As part of the piece, we interviewed Rosa repeatedly about her evolving relationship with the butterflies."

Letter from Gail Morris: Western Monarch Winter 2021–22 Report #1

In the Western U.S., Gail Morris relays more good news from overwintering sites in California and shares results from a lesser-known Thanksgiving Count in Arizona. Gail writes, "The news about Western Monarchs this year continues to be amazing, especially after the extremely small number counted just a year ago. The Xerces Society reported over 200,000 monarchs along the California coast, and everyone is eager to hear the final Thanksgiving Count. This week monarchs were reported primarily in California and Arizona, a harbinger of the winter season in the West . . . While well-known and new California monarch overwintering sites are the primary focus of the annual Thanksgiving Count, you might be interested to know Arizona winter monarchs are also at a few locations."

Monitor Overwintering Monarchs in Southeastern U.S.

Journey North is again excited to partner with the Georgia Department of Natural Resources, the University of Georgia, Monarchs Across Georgia, and an increasing number of partners to encourage people to report winter monarch sightings in the Southeastern U.S. from December through March. If you live in the Gulf states of Texas, Louisiana, Mississippi, Alabama, and Florida as well as Georgia, South Carolina and North Carolina, we want to hear from you.

Not all monarchs migrate to Mexico. Some breed throughout the winter in the southeastern U.S., and scattered reports show that other monarchs might overwinter in this region in a non-reproductive state. Researchers and others studying monarchs seek your help to understand this phenomenon.

What to Report

There are three types of observations you can submit to Journey North: