The Second Western Monarch Summit organized and hosted by Western Monarch Advocates (WMA) was held in San Luis Obispo during January 20-22. I was privileged to be a keynote speaker at this meeting which was attended by a true cross-section of Monarch advocates. This is what makes the Summit so unique. It is not a gathering of scientists alone it is a gathering of everyone who loves Monarchs! And it is this unique blend of advocates and scientists that leads to exceptional education and excitement.

On my way to the summit, I wanted to get an update on how Monarch populations at coastal overwintering sites coped with the atmospheric hose that they endured from soon after Christmas until mid-January. Ten major storms hit the California coast during this period. I visited 11 overwintering sites during January 18-21 under good weather conditions (sunny, 55-65 F) to estimate population size and to compare it to estimates I made at each site during November 21-23.

I saw an estimated 54,858 Monarchs at the 11 sites in January compared to 87,500 in November. This is a loss of about 37.3% which is close to the average % loss of Monarchs between Thanksgiving and New Year for the past four years (39%). Although my sample size was small, these data provide some optimism that the overwintering population was not substantially damaged by the three weeks of strong storms.

I saw big differences in how the populations at different sites weathered the storms. Gully-like overwintering sites oriented towards the coastline may have become ‘wind-tunnels’ in the storms and these sites had the least number of butterflies remaining. Conversely, overwintering sites within climax woodland (e.g. Pacific Grove) appeared to have weathered the storms best with minimal loss of butterflies. One of these sites near Pismo Beach actually doubled its population.

It is interesting and salient to note that none of the sites showed substantial mortality of butterflies had occurred. Dead butterflies on the ground were uncommon at all sites. Instead, it appears that butterfly loss at sites was likely a result of wind-driven dispersal inland. These butterflies, although now likely alone, still have a good chance of surviving the next few weeks, until the normal time the colonies begin their break-up in the latter half of February. If temperatures in coastal California remain below 70 F during this period (as forecast), reproductive dormancy will be maintained and the need to lay eggs prevented. While mating is beginning to occur at overwintering colonies, the ovaries of most females do not yet contain mature eggs.

Although limited, my survey provides a good prognosis for survival of most of the remaining overwintering Monarchs in California. How well this population repopulates the greater west in the coming months depends a lot on the weather conditions over the next 6-8 weeks.

Finally, the Summit concluded with a new sense of optimism for survival of the Monarch in the west. There is no doubt, that the Monarch has an army of committed supporters, all working hard to provide and protect habitat, reduce pesticide use and to spread the word that the king of butterflies, and all butterflies need our care and attention.

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