Western monarchs rebound to final tally of nearly 250,000 butterflies

By Isis Howard & Emma Pelton on January 24, 2022

Launched in 1997, the Xerces Society’s Western Monarch Thanksgiving Count celebrates its 25th year of community science with a surprising and remarkable outcome: 247,237 monarch butterflies observed across western overwintering sites, an over 100-fold increase from last year. However, the population remains more than 95% below its size in the 1980s, when low millions were observed most years. 

This year’s total both amazed us with the monarchs’ ability to bounce up from a record low and underscores the importance of ongoing conservation efforts to recover the western monarch butterfly population.

Graph showing the western monarch thanksgiving count totals and number of sites surveyed from 1997 to 2021.

Summary 2021 Thanksgiving count findings

Despite the challenges of conducting community science during yet another pandemic year, Thanksgiving Count volunteers surveyed 283 overwintering sites, 33 more sites than last year and an all-time record high in volunteer effort since the inception of the count. The 2021 Thanksgiving Count total of 247,237 illustrates a considerable rebound from 2020’s all-time low of less than 2,000 monarchs, which was preceded by two years of less than 30,000 monarchs. Thanks to our volunteers and program partners, there are now 25 years of Thanksgiving Count data demonstrating that western monarchs have undergone a significant decline estimated at more than 95% since the 1980s.

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