The monarch butterfly is a remarkable rebound from years of near- extinction, as thousands of the butterflies fill tree branches with their orange wings.
The monarchs have not reached half a million since the 1990s. The population of monarchs in the state plummeted to a new low in the winter of 2018, according to a count conducted by the Xerces Society for Invertebrate Conservancy.
The butterflies hit a record low last year.
Sarina Jepsen, director of the Xerces Society's endangered species program, told Insider that they were concerned last year that there would be no monarch butterflies in the Western US.
More than 100,000 monarch butterflies have been counted so far this year. Volunteers will continue to count through December 5. The final report from the Xerces Society will be published in January.
Jepsen said they were happy with the numbers. She said that this is not yet the recovery of the Western monarch population.
A lucky year for monarch butterflies may allow them to spend more time together.
Scientists don't know what's causing this resurgence and aren't sure if it will last. The uptick could be simple luck.
Jepsen said that it is not uncommon for an insect population to bounce around from year to year.
This year's explosion of butterflies could be a sign that it's not too late to save the monarchs. The butterflies are one of nearly half a million insect species that are declining in the face of pesticides, habitat destruction, and climate change.
In a recent post for the Xerces Society, biologists Emma Pelton of the Xerces Society, Elizabeth Crone of the Tufts University, and Cheryl Schultz of Washington State University explained that low butterfly populations can be very "bouncy" from year to year.
The biologists wrote that small populations mean individual butterflies aren't competing for resources. If it's a good year for milkweed, there's plenty to eat and room for the population to grow. monarch populations can spike rapidly because they can produce three or four generations per year.
Scientists don't know which factors are driving the swell. They can only speculate.
The monarch's breeding grounds are in Mexico and California. Butterflies benefit from warm, dry summers. Changes in the timing and location of California's wildfires could affect the butterflies' migration.
The Center for Biological Diversity says that Eastern monarch populations are declining, occupying 80 percent less forest than they did two decades ago.
There was a brief relief from conditions that hurt monarch migration. Scientists are looking into whether pesticide use in California's Central Valley could be a factor in the decline of monarchs. Some researchers suspect that parasites may spread to monarchs that live in California year round.
It is not possible to say if the population is clawing its way back from the brink or if it is just a blip in the migration's decline. We won't know this until we 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217 800-273-3217
Monarchs have a long way to go back from extinction.
This year's count is promising, but it's only half of what it was five years ago.
The US Fish and Wildlife Service estimates that the Western monarch populations will reach a point where extinction is inevitable within 60 years. The probability of extinction in the East is 74 percent.
The rebound doesn't improve the odds.
Jepsen said that restoring the monarch's habitats would tip the odds in their favor. In state parks, planting more native wildflowers and milkweed is important.
Reducing the use of pesticides along the butterflies' migration path in the Central Valley could help, although scientists are still researching the effect the chemicals have on monarchs.
President Joe Biden's $1 trillion infrastructure bill included money for pollinator preservation. The legislation creates $10 million in grants for local governments to build habitats for the monarch and pollinator.
Jepsen said that there was a lot of work to be done to recover the population, but that the new numbers gave them hope.
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