Western Monarch Butterfly | Cal Parks

Western Monarch Butterfly

Once, millions of monarchs overwintered along the Pacific coast in California and Baja, Mexico. In the 1980s,  an estimated 4.5 million butterflies migrated to the coast annually. But by the mid-2010s, the population declined to 200-300 thousand butterflies. And in both 2018 and 2019, volunteers counted under 30,000 monarchs — less than 1% of the population’s historic size.   

In 2020, volunteers counted less than 2,000 monarchs — that’s less than 0.01% of the historic size.    

Western Monarchs living west of the Rockies migrate to the coast of central and southern California. In October, as colder weather approaches, the butterflies instinctively know they must fly south to escape the freezing temperatures. Some have to fly over 1,000 miles. By November, most are sheltering in trees across California – and many are in California state parks!  

One of the significant problems afflicting western monarchs is habitat loss in their overwintering and breeding areas.  

California state parks provide shelter and protection for this iconic species. Home to key monarch overwintering sites and located along important migration routes, the California state park system holds critical habitat for Western monarchs. At California State Parks Foundation, we’re working throughout California to restore habitat, improve migration corridors, and engage the public in stewardship so future generations can experience the wonder and beauty of monarchs for many years to come.   

Monarch at Natural Bridges State Beach
6 ways you can protect the western monarch
Monarch cluster Natural Bridges State Park
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Raise awareness and encourage your friends and family to take steps to protect the western monarch.