The number of western monarch butterflies wintering along the California coast has plummeted precipitously to a record low, putting the insects closer to extinction, researchers announced Tuesday. An annual winter count by the Xerces Society recorded fewer than 2,000 butterflies, a massive decline from the millions that clustered in trees from Northern California's Marin County to San Diego County in the south in the 1980s, reports the AP. The Xerces Society, a nonprofit environmental organization that focuses on the conservation of invertebrates, recorded about 29,000 butterflies in its annual survey last winter. That was not much different than the tally the winter before, when an all-time low of 27,000 monarchs were counted. But the count this year is dismal. At iconic monarch wintering sites in the city of Pacific Grove, volunteers didn't see a single butterfly.
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 to keep warm. The monarchs generally arrive in California at the beginning of November and spread across the country once warmer weather arrives in March. Scientists say the butterflies are at critically low levels in western states because of destruction to their milkweed habitat along their migratory route as housing expands into their territory and use of pesticides and herbicides increases. Researchers also have noted the effect of climate change, and massive wildfires in the west may have influenced their breeding and migration. This 2017 study predicted that if the monarch population dropped below 30,000, the species would likely go extinct within a few decades, unless given help.
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