of collapsing as well due to erosion by wind and waves. Visitors were formerly permitted to climb up, walk and even drive on the bridges. Now the arch is closed to public access. Ecology Natural Bridges State Beach is home to a eucalyptus grove that provided habitat for monarch butterflies. Up to 150,000 butterflies migrate up to to the park to escape the cold weather of winter in the northwestern United States and Canada. The city of Santa Cruz holds an annual festival to mark the return of the butterflies. Monarchs settle in groves along the coasts of California and Baja California. At Natural Bridges State Beach they find shelter from the wind and sources of water and food. The butterflies cluster onto the trees, "intertwining their legs among the branches to resemble a clump of leaves." The butterflies protect each other from cold winter winds and rains by clustering together. Beginning in the late 1990s the population of butterflies at the park began to decline. Biologist attribute the decline to a lack of habitat caused by fallen pine and eucalyptus trees. The decline at Natural Bridges State Beach has meant an increase in butterfly numbers at nearby Lighthouse Field State Beach. The of the park have a variety of habitats. Saltwater and freshwater marshes are found on Moore Creek. Coastal Scrub surrounds the margins and undeveloped interior areas of the park. Sand dunes and a fresh water pond are also found at the park. Tide pools at the beach provide a glimpse into marine life habitat for visitors to the park. Receding tides reveal populations of urchins, sea stars, hermit crabs, and kelp. Marine mammals, such as whales, seals, and sea otters can be seen from the beach. In combination with the estuarine mouth of Moore Creek, the state beach provides habitat for a variety of bird species, such as shorebirds, gulls, and snowy egrets. Brown pelicans and cormorants can often be found on the remaining natural bridge. Natural Bridges State Marine Reserve is a marine protected area off the coast of Natural Bridges State Beach. Like an underwater park, this marine protected area helps conserve ocean wildlife and marine ecosystems. Recreation Natural Bridges State Beach is open to year-round recreation including swimming, surfing, hiking, nature walks and picnics. The beach is small and sheltered. The afternoon winds attract kite flying and wind surfing. The beach is open to