More than 129,000 western monarch butterflies were counted in the [San Luis Obispo] county by Xerces Society for Invertebrate Conservation employees and volunteers in November, according to preliminary data shared by local volunteer coordinator Jessica Griffiths.

That’s the most counted in San Luis Obispo County in more than 20 years — in 1998 there were about 182,000 counted, according to the Xerces Society’s data. The numbers are giving some researchers hope that the western monarch butterfly population could be rebounding from devastatingly low numbers a few years ago that left some worrying the insect was on the verge of extinction.

It’s hard to tell exactly why there are more monarch butterflies fluttering around overwintering groves, Griffiths said.

Part of that is because there are simply more groves being counted: 55 sites were surveyed in San Luis Obispo County this year, she said, up from 51 last year. That number has been rising nearly every year as community members keep an eye out for the insects and report them to the Xerces Society.

The biggest overwintering groves in the county include the Pismo Beach Monarch Butterfly Grove along Highway 1, along Pecho Road in Los Osos, at the Morro Bay Golf Course, within the Fiscalini Ranch Preserve and scattered around dozens of private properties, according to the Xerces Society.

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