State of the Monarch Butterfly Overwintering Sites in California

This report provides an assessment of overwintering sites of western populations of the monarch butterfly in California.  From data collected at over 400 sites, the report summarizes existing overwintering trends and identifies the highest priority sites for active management and protection.

State of Overwintering Sites_cover_june2016





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Western Monarchs in Crisis
Save Western Monarchs!

The western monarch migration is on the verge of collapse. Learn more, including how to help.

Help Save Monarchs: Plant Milkweed!

Milkweed species support monarch butterflies, native bees, honey bees, and other beneficial insects. Search for sources of milkweed seed now!

Pollinator Conservation Resource Center

The Resource Center is where you can find regional information about plant lists, habitat conservation guides, and more. Learn more.

Monarch Conservation News
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  • Working to Conserve Monarchs from Coast to Coast

  • New iNaturalist Project Makes it Easier to Submit Data to the Western Monarch Milkweed Mapper

  • Gardening for Butterflies
    Gardening for Butterflies
    Our newest book introduces you to a variety of butterflies who need our help, and provides suggestions for native plants to attract them, habitat designs to help them thrive, and garden practices to accommodate all their stages of life. Click here to read more
    On Captive Breeding and Release of Monarchs
    OE infected monarch
    Following news of the dramatic decline in monarch numbers, some people are rearing large numbers of monarchs in backyard operations or obtaining them from commercial breeders or other organizations and releasing them with the goal of supplementing local populations. But are such efforts doing more harm than good? Click here to read more