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Many monarchs in a cluster

SANTA CRUZ, Calif.--For years, large populations of monarch butterflies have migrated to the central California coast each winter in search of stands of trees protected from the wind and cold. But since the early 1990s, the number of butterflies that make it to places like Natural Bridges State Beach here, or to the monarch sanctuary in nearby Pacific Grove, Calif., has dropped precipitously, from well over 100,000 per year to 10,000 or less today.

This is one of a very small number of clusters of monarchs that can be found today at Natural Bridges.

According to the experts, the reason for the dramatic fall in numbers is a general loss of milkweed throughout California, a plant that is required for the breeding of monarchs.

Now, as the population of monarchs that "overwinter" from late October through early March falls to dangerously low numbers, there is hope in the form of organized efforts to increase the amount of milkweed that is grown in California and elsewhere.

Updated:Caption:Photo:Daniel Terdiman/CNET
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Bring Back the Monarchs

In an effort to save the butterfly population, an organization called Monarch Watch is "initiating a nationwide landscape restoration program called 'Bring Back The Monarchs.' The goals of this program are to restore 19 milkweed species, used by monarch caterpillars as food, to their native ranges throughout the United States and to encourage the planting of nectar-producing native flowers that support adult monarchs and other pollinators."

Updated:Caption:Photo:MonarchWatch.org
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Monarch trail

The entrance to the protected monarch grove at Natural Bridges State Beach in Santa Cruz, Calif.

Updated:Caption:Photo:Daniel Terdiman/CNET
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One on the ground

Although most of the thousands of monarchs at Natural Bridges are hanging from trees, or are flying around at 35 feet or higher, this one butterfly was crawling on the ground, adding a splash of bright orange to the otherwise gray and brown landscape.

Updated:Caption:Photo:Daniel Terdiman/CNET
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Flying

A group of monarchs flies around in the trees at Natural Bridges State Beach in Santa Cruz, Calif.

Updated:Caption:Photo:Daniel Terdiman/CNET
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Monarch resting area

The sign at the front of the monarch resting area in Natural Bridges.

Updated:Caption:Photo:Daniel Terdiman/CNET
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Catching the late sun

A cluster of monarchs catches the last rays of the afternoon sun at the Monarch Grove Sanctuary in Pacific Grove, Calif.

Updated:Caption:Photo:Daniel Terdiman/CNET
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Lighthouse cluster

Another cluster of monarchs rests in the trees at Lighthouse Field State Beach in Santa Cruz, Calif.

Updated:Caption:Photo:Daniel Terdiman/CNET
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The emergence of the butterfly

According to a sign at Lighthouse Field State Beach in Santa Cruz, Calif., "Using an unusual survival strategy, monarchs lay eggs on toxic milkweed leaves where young caterpillars will hungrily forage. The caterpillars will accumulate these poisons and carry them into their adult stage, making them an untasty diet for most predators."

The illustration shows the emergence of a butterfly from its chrysalis form, and prior to that, its caterpillar form.

Updated:Caption:Photo:Daniel Terdiman/CNET
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A monumental migration

According to this sign at Lighthouse Field State Beach in Santa Cruz, Calif., "No other butterfly travels as far as the monarch--every fall they migrate as much as 1,500 miles to reach the moderate climate of their ancestral winter refuges. These tiny adventurers, four to five generations descended from the monarchs that wintered here last year, cluster on 'butterfly trees,' colorful wings closed. In balmy weather they flutter about, feed on flower nectar, and mate.

"Egg-laden females journey north in spring, stopping to deposit eggs on milkweed plants. In a few days, the caterpillar eats its way out of the egg casing and feeds on the milkweed. It sheds its striped outer skin multiple times as it grows, and eventually the skin hardens into a hanging shell-like chrysalis from which the adult butterfly emerges."

Updated:Caption:Photo:Daniel Terdiman/CNET
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Butterfly crossing

A sign at Natural Bridges State Beach announces the monarchs.

Updated:Caption:Photo:Daniel Terdiman/CNET
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Solo monarch

A monarch hangs off a tree branch.

Updated:Caption:Photo:Daniel Terdiman/CNET
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Monarch Grove Sanctuary

The entrance to the Monarch Grove Sanctuary, in Pacific Grove, Calif.

Updated:Caption:Photo:Daniel Terdiman/CNET
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PG cluster

Although its Web site suggests that 25,000 monarchs overwinter there each year, there are less than 5,000 this winter at the Monarch Grove Sanctuary in Pacific Grove., Calif. This is one of the small number of clusters of butterflies that can be found there.

Updated:Caption:Photo:Daniel Terdiman/CNET
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Big Lighthouse cluster

A large cluster of butterflies at Lighthouse Field State Beach in Santa Cruz, Calif.

Updated:Caption:Photo:Daniel Terdiman/CNET
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Bench

A bench in the shape of a monarch butterfly at the Monarch Grove Sanctuary in Pacific Grove, Calif.

Updated:Caption:Photo:Daniel Terdiman/CNET
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Monarchs on eucalyptus

A cluster of monarchs rests in the eucalyptus leaves at Natural Bridges State Beach in Santa Cruz, Calif.

Updated:Caption:Photo:Daniel Terdiman/CNET
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Close-up

A close-up of a cluster of monarchs.

Updated:Caption:Photo:Daniel Terdiman/CNET
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