The Washington Post reports that the monarch butterfly population wintering in Mexico has shown a drop in six of the last seven years. “…There are now only one-fifteenth as many butterflies as there were in 1997,” the article says.
Journey North reports that this year’s population is lowest since record-keeping began.
Drought and herbicides that have killed off milkweed, which the monarchs require as host plants — particularly in the Midwest, are thought to be the main contributors to the decline. While populations have rebounded after drops, the overall trend is down, down, down.
Photo: Monarch butterfly by Mark Musselman, used courtesy of the US Fish and Wildlife Department.