Western monarch butterfly population still at critical level

Historically, an estimated 4.5 million monarchs overwintered on the California coast. In the last two years, the population has hovered around 29,000, less than 1% of historic levels.

PORTLAND, Ore., January 23, 2020—The Xerces Society today announced that the number of monarch butterflies overwintering in California remains at critical levels for the second year. The monarch population during the 2018–19 winter was an all-time low. Unfortunately, this year’s Western Monarch Thanksgiving Count numbers are no better.

The total number of monarchs counted this year was 29,418. Although this is 2,200 more than last year, it comes as a result of greater survey effort, with volunteers visiting more sites. There is no meaningful difference between the western monarch population this year and last.

In addition, in both years the population has been less than 30,000 butterflies, the threshold below which the migration may collapse.

“We are disappointed by the numbers of year’s Western Monarch Thanksgiving count,” said Emma Pelton, the Xerces Society’s Western Monarch Lead. “We had hoped that the western monarch population would have rebounded at least modestly, but unfortunately it has not. The silver lining is that the population didn’t shrink any further. There are still thousands of monarchs overwintering along the coast, so we can take heart that it’s not too late to act.”

Read the rest of the press release here, and a blog here.