Experts aflutter over monarchs

There is a ray of hope for the vanishing orange-andblack Western monarch butterflies.

The number wintering along California’s central coast is bouncing back after the population, whose presence is often a good indicator of ecosystem health, reached an all-time low last year. Experts pin their decline on climate change, habitat destruction and lack of food due to drought.

An annual winter count last year by the Xerces Society recorded fewer than 2,000 butterflies, a massive decline from the tens of thousands tallied in recent years and the millions that clustered in trees from Northern California’s Mendocino County to Baja California, Mexico, in the south in the 1980s. Now, their roosting sites are concentrated mostly on California’s central coast.

This year’s official count started Saturday and will last three weeks, but already an unofficial count by researchers and volunteers shows there are more than 50,000 monarchs at overwintering sites, said Sarina Jepsen, director of Endangered Species at Xerces Society for Invertebrate Conservation.

“This is certainly not a recovery, but we’re really optimistic and just really glad that there are monarchs here and that gives us a bit of time to work toward recovery,” Jepsen said.

Western monarch butterflies head south from the Pacific Northwest to California each winter, returning to the same places and even the same trees, where they cluster. The monarchs generally arrive in California at the beginning of November and spread across the country once warmer weather arrives in March.

The Western monarch butterfly population has declined by more than 99 per cent since the 1980s.

On the eastern side of the Rocky Mountains, another monarch population travels from southern Canada and the northeastern United States across thousands of miles to spend the winter in western Mexico. Scientists estimate the monarch population in the eastern U.S. has fallen about 80 per cent since the mid-1990s.

Whether the population of monarchs that fly to Mexico from the eastern side of the country has rebounded is not yet known. Results of an annual county by experts with the World Wildlife Fund in Mexico won’t be released until next year.

Scientists don’t know why the population increased this year, but Jepsen said it is likely a combination of factors, including better conditions on their breeding grounds.