Saturday, April 2, 2016

Dear Friends,
The season is now at its end and, after the terrible winter storm that hit the monarchs sanctuaries of the region, some scientific observations and measurements have recently been made. The goal is to estimate the level of mortality the storm caused.

I was honored to have been allowed to join the scientific team during this very interesting visit and investigation. The team consisted of Dra. Isabel Ramírez and Dr. Pablo Jaramillo, both of UNAM (Universidad Nacional Autónoma de México) in Morelia. American teacher Mr. Dave Kust also volunteered to come to Mexico to help. Dave was in Angangueo on a teaching sabbatical when the January 2002 storm struck and he participated in the data collection then. Also present were Dave’s son and daughter.

We visited the Cerro Pelón and Sierra Chincua Sanctuaries on March 25 and 28, respectively. Were not able to obtain permission to collect at El Rosario.

We repeated the same protocol that was followed by Dr. Brower and team in 2002*. The methods consisted of laying transects (parallel lines) "covering" the area where monarchs had been the moment the winter storm came.

We took 5 samples along each transect.  Each sample was a handful of any number of dead (and seldom a semi-dead) monarchs. The samples were placed in a plastic bag then sorted into the following categories:  

1.- Male
2.- Female
3.- Bird predated
4.- Long dead
5.- Recently dead
6.- Torn pieces

Once the samples of monarchs were sorted, we had to spread them all back around to the ground. In Cerro Pelón we sorted out 16 sample bags and we were several people, so all was easy and quick. In Sierra Chincua we sampled 50 bags. 

Here are some observations made during this important visit to our Sanctuaries:

1.-Very intense winds hitting the forests last 8-9 March felled many trees. It was confirmed, as commented in our last report, that the wind’s direction kept mainly from south to north. Most fallen trees and canopy lie now in a south-north orientation.

2.- It seems that there was more mortality in El Rosario, less in Sierra Chincua, and in Cerro Pelón. The pictures in the slideshow above that show the forest floor covered with monarchsare all from El Rosario. One can see the impressive numbers. One reason for the difference between sanctuaries could be because each sanctuary has different kinds of forests and the butterflies were living in different parts of those forests.

3.- In Cerro Pelón, it was odd that some monarchs seemed to be dead on the trunks of Oyamel trees. Dr. Lincoln Brower was very surprised to hear this. He does not remember having seen this in the freeze event of January 2002.

4.- Many dead Monarchs in Sierra Chincua showed dry, fragile wings and abdomens. In Cerro Pelón, wings and bodies in some cases seemed more flexible and soft.

5.- In El Rosario, there was active mating (on March 28), that wasn’t observed in the two other Sanctuaries, Pelón or Chincua.

Estela Romero
Journey North Correspondent
Angangueo, Michoacán, México
April 2, 2016

* Brower, L. P., D. R. Kust, E. Rendon-Salinas, E. G. Serrano, K. R. Kust, J. Miller, C. Fernandez del Rey, and K. Pape. 2004. Catastrophic winter storm mortality of monarch butterflies in Mexico during January 2002. Pages 151-166 in K. S. Oberhauser and M. J. Solensky, editors. The Monarch Butterfly. Biology and Conservation. Cornell University Press, Ithaca.