News

Monarch butterfly numbers have plunged

Monarch butterfly populations in Wisconsin last summer were the lowest in 25 years. For the past 25 years the Southern Wisconsin Butterfly Association has conducted butterfly counts between June 25 and July 16 at locations in Columbia, Fond du Lac, Grant, Trempealeau and Door Counties. The Milwaukee Journal Sentinel reports last year spotters found 0.54 Monarchs per hour of observation compared to 1.69 in 2012 and the lowest number since they started the count. The peak was 5.2 Monarchs per hour in 2010. Association members say 2010 was an ideal year with plenty of rain and warm temperatures while the drought of 2011 took its toll with the cold, wet spring in Wisconsin last year doing further damage.

The latest indication the Monarchs are in trouble comes from Mexico. Monarchs from the central and eastern United States spend winters in close concentration in the fir trees of the trans volcanic mountains in central Mexico. Because they are so concentrated, thousands in each tree, they are counted by the area covered. In a report this week, The World Wildlife Fund and Mexico’s Environmental Department cites as an example of the decline, an area west of Mexico City which covered 1.65 acres this year compared to 2.92 acres last year and a peak of 44.5 acres in 1996.

Besides the weather, a loss of habitat has also contributed to the decline. Monarch advocates encourage people to visit Monarchwatch.org to learn how to create habitats for caterpillars and nectar for the butterflies.