Populations of one of the most recognisable and well-studied butterflies are nearing collapse. Scientists studying this year's migration of the Western Monarch recorded less than 2,000 butterflies, compared to the millions migrating in the 1980s. The Xerces Society's 24th Western Monarch Thanksgiving Count recorded only 1,914 monarch butterflies moving south to California's coast to stay warm over the winter this year. According to the organisation that's a 99.9% fall from the number of monarchs in the 1980s when butterflies filled trees from Marin County to San Diego County. This critically low number follows the previous 30,000-butterfly threshold recorded from 2018 to 2019—less than 1% of the population’s historic size, despite the volunteers visiting even more overwintering sites compared to the previous year.