Western monarch butterfly numbers float downward

Since 1997, the Xerces Society for Invertebrate Conservation has coordinated a monarch butterfly count along the California coast, where western monarchs spend their winters. This year’s count was 9,119, the second lowest number since the group’s counts began.

Each of the previous three years produced counts of more than 200,000 butterflies.

Pesticides, a lack of milkweed (which monarch caterpillars need), diminished habitat and changing weather are key factors in the decline of the monarch.

What specifically caused this year’s precipitous drop? Here’s what Emma Pelton of the Xerces Society said: “The record high late summer temperatures and drought in the West likely contributed to the significant drop-off we saw.”

Due to a decades long drop in the insect’s population, the U.S. Fish and Wildlife Service proposed in December to add the monarch butterfly to the Endangered Species Act and classifying it as “threatened,” meaning it’s less at-risk than “endangered.” These new protections would cover the western monarch and its eastern brethren, and would give these orange-and-black flyers a fighting chance to recover — and then get off the list.

This latest count on the West Coast provides additional evidence that the agency should protect the monarch butterfly.