By Rick Mikula (December 2018)
The Monarchs were a bit late this year in getting to their overwintering sites but that is not a bad thing. Their arrival time always fluctuates and this year between a late start due to warmer temperatures, countless rainstorms and dipping temperatures towards the end of migration they still made it home. I say home because many scientists believe that the species originated in Central Mexico and through natural dispersal they followed the milkweed as it followed the receding glaciers of the last Ice Age. Visiting the US and Canada is just a summer “Road Trip” for them but the ancestral home is still Central Mexico.
All of the monitoring sites reported good numbers but everybody passed through a little later than normal. It may have been the constant rain we seemed to have all Summer or it could have been a warmer Fall but they were late in leaving but they still came through. The overwintering counts have begun yet since thousands and thousands are arriving by the day. Last week, in Cerro Pelon, Monarchs filled the skies with constant activity and colonies are popping up everywhere. Judging by the daily arrivals the ranger that protect and monitor the sites are predicting a banner year. So let us keep our tarsi crossed that they are right.
On the other hand the West coast researchers are feeling just the opposite. They are finding the fewest numbers of Monarch butterflies in central California than they have recorded in past 46 years. They surveyed 97 sites and found only 20,456 Monarchs compared to 148,000 located at the same sites last year. Many now fear that the Western population has fallen by 97% since the 1980s!
As usual the biggest culprits over the years have been are habitat loss and the wide spread use of pesticides across the butterflies’ breeding and migratory range. Data from the pesticide national synthesis project shows that between 1997 and 2014 the amount of Roundup applied to herbicide resistant corn and soybean crops increased from an estimated 500,000 to 100 million kilograms. Because of its rampant use it has been estimated that since 1999 Roundup has caused the loss of 40-50 percent of the common milkweeds in the Midwest. It is heart breaking to think how many more plants has been lost through urban sprawl and highway infrastructure.
The Mid-west is not alone. California farmers also applied Roundup to more than 200 crops across 4 million acres, including 1.5 million acres of almonds, making it their most widely used herbicide, according to California’s Department of Pesticide Regulation. And it is not just soy bean and corn that are sprayed. Recently the group, Moms Across America, sent sample of 10
California wines to be tested for glyphosate. All of the samples tested positive for glyphosate even the organic wines. Whether it is a vineyard or an avocado farm they are surrounded by host plants that soon fall victim to Roundup.
Although the west coast experienced horrendous Spring rainstorms California’s state forests never had a chance to recovered from the previous 7 years of record-breaking droughts. If that was not enough the catastrophic wildfires devastated them even more and at the most crucial time of migration robbing the migrants of roosting trees and nectar plants. So between Mother Nature and the continuous use of pesticides is seem amazing that we have any Monarch left at all.
That is why we cannot emphasize enough the importance of creating habitat whether it is in your garden or on a wider scale. All species of butterflies need our help but right now Monarchs need it most of all.
This entry was posted on December 4, 2018.