Signs of Colony Break-up Signal Spring
Monarch Butterfly Field Notes from Mexico by Dr. Bill Calvert

February 27 , 2009
Bill Calvert and Bonnie Chase of the Monarch Watch of Texas are here in Mexico with The Raptor Trust of New Jersey, world famous for its raptor research and advocacy and for patching the wings and repairing the sinews of wild birds of all species.

Cold Weekend Weather Included Hail
After a cold weekend replete with a twenty-three-year-record hail fall in Morelia that caused the populace to turn out into the streets to build snow (hail) men and throw hail balls at each other, the temperature gradually returned to seasonal averages.

Two Kinds of Clusters at Chincua: One a Sign of Colony Break-up
We arrived late at Chincua and trudged down the twisted path of the Arroyo La Planca (also know as the Arroyo Hondo) on reluctant horses to find butterflies returning to their afternoon roosts. The colony, less than a hectare, was strung out along a side arroyo that lead upwards to the Llano de los Toros and the famous Brower point.

Both dense butterfly clusters (from the earlier January colony)—and loose clusters high in the trees —were present. The latter indicate that the colony is beginning its spring expansion and break up. No trunk clusters were present, although the Vigilantes guarding the colonies would not allow us into the more dense clusters.

Monarchs at Rosario Dazzled All Present
The following day, after debating our best sighting and observation options, we ascended the mountain to the ejido community of Rosario, paid our admission fees, and walked up the 627 stairs and long, twisted path to the Llano de los Canejos. The first indications of the delights to come were the tens of thousands of butterflies swarming over the llano, and thousands nectaring and drinking from mudflats, seeps, and open waters. A short path from the llano led us into the forest where we saw tens of thousands more soaring downward, basking on sun-drenched foliage, and watering. We finally arrived at the clusters in the headwater of the Arroyo Grande above the community of La Salud. Scores of matings were observed. Likely due to a high pressure cell above us and cloudless skies, the butterflies at Rosario were extremely active and dazzled all present with their spirited exuberance. In closing, we must add that the oldest of us who made the trek up the mountain was 81 years of age.

Dr. Bill Calvert


Hail fell at the El Rosario monarch sanctuary too on Saturday, Feb. 21st while Estela Romero was visiting.



The presence of loose clusters indicate that the colony is beginning its spring expansion and break up.



Extremely active butterflies dazzled all present with their spirited exuberance.