Monarch butterflies have migrated to the eucalyptus grove of Natural Bridges State Beach in Santa Cruz this fall with numbers officials haven't seen in years.

The park's Monarch Grove provides a temporary home for up to 100,000 Monarchs.  From late fall into winter, the Monarchs form a "city in the trees."   The area's mild seaside climate and eucalyptus grove provide a safe place for monarchs to roost until spring.

There were hundreds of visitors armed with cameras and binoculars on Dec. 2 getting a glimpse of the well-known insect.

Natural Bridges interpreters estimate there are about 6,000 monarchs settling at the state beach this year.

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In the spring and summer, the butterflies live in the valley regions west of the Rocky Mountains where the monarch's companion plant, milkweed, is found.  For most of the year, where there are monarchs, there are also milkweed plants.  Monarchs drink nectar from milkweed flowers, and female monarchs lay their eggs on milkweed leaves.  Milkweed contains a toxin that, when ingested by the caterpillar, makes it toxic to other animals. These toxins remain in the butterfly as well, providing protection from predators that would otherwise eat the monarchs.  

Docent-led butterfly, tide pool and nature trail tours are available. Large groups should reserve beach use and tours by phone at least 2 weeks in advance. Special event reservations should be made at least 1 month in advance.

Visitors can view the over-wintering Monarchs by walking down the park's wheelchair and stroller-accessible boardwalk to an observation deck in the eucalyptus grove.

Natural Bridges is located at 2531 W Cliff Dr., Santa Cruz.

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