Monarch butterflies on the move through Alameda County

October 22, 2026

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butterflies were recorded 6 times in October (most recent 2026-10-21) across Alameda County and the region, including at Broadmoor District and Yerba Buena.¹ The species is federally Proposed Threatened; mid-to-late October is peak movement as monarchs migrate southward to overwintering sites in Mexico.^1, 2

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