Painted lady butterflies pause to feed on the nectar of California’s superbloom near Thousand Palms. David McNew/Getty Images Currently, skies in Southern California look like a scene out of Hitchcock—a little less moody, maybe, and a bit more ethereal. From Burbank to Redondo Beach to South Central Los Angeles and beyond, swarms of butterflies have been flitting throughout the air in a fever dream of irruption and migration. And with the overall numbers of these tiny, two-to-three-inch butterflies, known as painted ladies (Vanessa cardui), appearing to be down in the region (from around 300,000 in 2017 to 25,000 last year, according to one monitoring program), this magical burst of lepidopterans brings both wonder and hope. The painted lady fluorescence is the result of an unusually rainy winter in California—and in the deserts in particular, which also helped spur this spring’s wildflower superbloom. In a statement, James Danoff-Burg, conservation director of the Living Desert Zoo and Gardens, said “the average annual rainfall in the Coachella Valley is three inches. This year, we had three and a half inches on Valentine’s Day alone.” Art Shapiro, an ecologist at University of California, Davis, who’s been studying butterfly migration since 1972, told CNN that “Painted ladies tend to thrive when there’s a superbloom because there are so many plants for the butterflies to lay their eggs on and for caterpillars to eat.” While these butterflies migrate from Mexico every year, through Southern California’s deserts, to the Pacific Northwest, they usually go relatively undetected because there aren’t quite so many of them. This year’s phenomenon is referred to as an irruption. “The difference is that a migration is a seasonal occurrence,” says Matthew Shepherd of the Xerces Society, an invertebrate conservation nonprofit based in Portland, Oregon. “An irruption is a sudden and massive surge in population size that doesn’t happen each year. Essentially, there is a super-abundance of something that leads to a population that is so large that the pressure just keeps pushing the butterflies on the edges further and further is search of flowers.” Another reason the critters are making their way up the coast from Mexico, where they winter in the Sonoran Desert, is because of this crowding. “The pressure of having so many butterflies in one area is forcing them outward,” says Shepherd. “The mass of host plants that the caterpillars eat is as important to this as the availability of nectar to fuel the adults. The butterflies are not so much leaving something behind, but moving in search of plants and areas that aren’t saturated with other painted ladies!” A lovely painted lady in a moment of pause. Renee Grayson/(CC BY 2.0) The small insects flitting through California’s vistas are cousins of the larger and more vibrant monarch, which faced critically low population numbers (down 85 percent) in California last year. Both butterflies are similar in color—orange and black with whispers of white—and are essential pollinators of the state’s plants. Tom Merriman, director of the Encinitas-based butterfly nonprofit Butterfly Farms, says that butterflies “can get into flowers bees can’t get to,” and that “monarchs are considered an indicator species that help us judge the condition of our environment.” According to Merriman, the last time Southern California an event like this was in 2005, an El Niño year. (Then, I-5 was closed in Southern California due to the quantity of dead butterflies on the road surface, Shepherd says.) That wet year, there were estimated to be more than a billion painted ladies. Based on the butterflies that flew through Encinitas just yesterday, Merriman ventures that the region is seeing just as many. “They’re moving pretty quickly and can travel nearly 30 miles per hour and can cover up to 100 miles a day,” Merriman says. Occasionally, the ladies stop to sip nectar from flowers, and then continue their haste. “Think cars traveling on the freeway, they’re all going the same direction but not really together,” Merriman says. “We think it’s going to go on for a few more weeks. They’re not going to be as dense—some will run out of energy and stop to feed and breed, some will run into predators, or worse, automobiles.” The painted ladies are expected to stay, wherever they settle down, throughout the summer. Shepherd’s guess is that they’ll arrive in Oregon sometime in April. They’ll make offspring, and the ones flying north now will almost certainly be grandparents by July. For most of them, the Pacific Northwest will be the end of the road. “Painted ladies mostly die where they are at the end of the season,” Shepherd says, because their average life expectancy is two to four weeks. Then their descendants will travel back to Mexico in the fall.<doc-sep>First came the chartreuse hillsides. Then the purple, yellow, and white wildflowers. Now, there are orange and black butterflies. They’re painted ladies, to be exact. By the millions, the butterflies are fluttering through Southern California, feasting on a proliferation of herbaceous plants like cheeseweed and hollyhock. It’s part of their normal movement north from the dry deserts of Mexico to the lush Cascade Range in the Pacific Northwest. But the population is outsized this year, the latest colorful natural phenomenon produced by winter’s abundant rainfall and a cooler February that has kept the plants from drying out. “In good rainy years, the migration is really noticeable,” says Brian Brown, curator of entomology at the Natural History Museum of Los Angeles County. Brown says their movement through Southern California probably started about one week ago. That’s when residents started calling into the museum to report what they were seeing. The painted ladies have been spotted flickering around Los Angeles, from the Walk of Fame to South Bay beaches, and across Southern California, including in and around Palm Springs. Doug Yanega, senior museum scientist at UC Riverside’s Entomology Research Museum, said he and his colleagues spent their lunch break today counting butterflies. “We were seeing at least 100 of them a minute,” he says. “That’s just looking out one window. We’re talking about a population in the millions, easily no question.” In the deserts outside of Southern California, Yanega says there are caterpillars “everywhere.” “I know people who do field work out there, and they’re saying, ‘Holy crap,’” he says. Ian Recchio, curator of reptiles and amphibians at the LA Zoo, agrees that he’s seen more painted ladies on recent trips to the Mojave desert than he has in Griffith Park. “Unfortunately, I’m seeing most of them smash into my window as I’m driving,” he says. It takes the larvae about one month to reach development, so if the weather doesn’t get too hot or too dry soon, the high volume of butterflies could carry on for another month or even three months, Yanega says. “As long as there’s green vegetation, then we should be seeing them.” An adult butterfly typically only lives a couple of weeks. Their flight north is typically made up of multiple generations, with a butterfly going a certain distance, then laying eggs. Its brood will hatch and continue north. That’s similar to the famed migration of monarch butterflies, which are commonly mistaken for painted ladies. Brown says the movement of painted ladies isn’t as dramatic, but it is far more ubiquitous—painted ladies are found around the globe. “The migration is not only happening here in North America. It happens between Africa and Europe as well,” he says. “It really is a worldwide phenomenon.” Southern California friends: I just sat on the beach in the South Bay for two hours while 1,000s of butterflies flew around and past me. What kind are they? What is happening? #butterflies pic.twitter.com/n1IrEaBy0D — jessica. (@loveheylola) March 11, 2019 With rainfall 5.91 inches above normal in Downtown LA since October, according to the National Weather Service, Recchio says LA should expect to see more insects this spring. “The bottom line is we’re getting a lot of rain that equals more bugs—bugs of all kind,” he says. And that means more butterflies. Recchio says there are other types of lady butterflies that are more unique to Southern California that will benefit. “Southern California is a biodiversity hotspot,” he says. “We have amazing butterfly diversity in this part of the world.” But these painted ladies are native—and that’s something to celebrate, says Yanega. “It’s one of the few times where we can have an outbreak of something and be guilt free,” he says. “This is cool.”<doc-sep>Perhaps you spotted them on La Cienega, flitting north by the thousands near the Westfield mall. Maybe you saw them in Santa Anita, crossing a quiet residential street in a thick, fluttering line. For the record: An earlier version of this article said Art Shapiro had counted 25,200 Painted Ladies at 10 sites in 2018 and 315,997 a year earlier. The numbers are 27 and 512, respectively. You may have even commuted with hundreds of them along the 105 Freeway, where they furiously flapped their small wings as if they were trying to catch a flight at Los Angeles International Airport. Those black-and-orange insects that seem to be everywhere you look in Southern California aren’t monarchs and they aren’t moths. They are called painted ladies, and these butterflies are migrating by the millions across the state. Advertisement The migration itself is nothing new. Painted ladies set off from their wintering grounds in the Mojave and Colorado deserts of southeastern California as winter gives way to spring. They travel roughly the same path every year, flying northwest to Sacramento en route to Oregon, Washington and beyond. (They’ve been spotted as far north as Alaska.) What’s unusual this year is the number of 2- to 3-inch butterflies making the journey. Scientists say there haven’t been this many painted ladies traversing the state since 2005, when the population climbed to about 1 billion. “When they are scarce nobody notices them,” said Art Shapiro, an ecologist at UC Davis who has been tracking butterflies in the state for nearly 50 years. “When they are abundant, everyone notices.” James Danoff-Burg, the conservation director at the Living Desert Zoo and Gardens in Palm Desert, encountered a pack of butterflies while riding a bike through La Quinta last week. “They were flying parallel to me, just bobbing along as I rode past the date palms,” he said. “It was absolutely magical. I felt like a Disney princess.” Painted lady butterflies pause to feed on the nectar of California’s second “super bloom” in two years during a rare mass migration triggered by recent abundant rainfall on March 9, 2019, near Thousand Palms, Calif. (David McNew / Getty Images) The painted lady explosion is a welcome exception to California’s current butterfly crisis. The number of butterflies in the state has been in decline for decades, reaching historic lows in 2018, according to research conducted by Shapiro and others. Advertisement “It was a terrible — perhaps even catastrophic — butterfly year at all elevations and no, we don’t know why,” Shapiro wrote in a somber report. A monarch count led by the Xerces Society for Invertebrate Conservation in November found only 28,429 of the iconic orange-and-black insects wintering along the California coast. That figure represents an 85% drop from the previous year and a 99.4% plunge compared with 40 years ago. “In our grove alone we would have 250,000 monarchs in the 1980s,” said Danielle Bronson, a state park interpreter at Pismo State Beach. “This season we had about 3,000 at our peak.” Other butterfly populations have been hit even worse. Advertisement At least 20 species are disappearing faster than the monarch, said Matt Forister, an ecologist at the University of Nevada, Reno. They include the large marble butterfly (Euchloe ausonides), the field crescent (Phyciodes campestris campestris), the west coast lady (Vanessa annabella), the common sooty wing (Pholisora catullus) and the California ringlet (Coenonympha tullia california). “There are a lot of butterflies declining quite rapidly,” he said. No one is certain what is causing butterflies in California to disappear, but researchers have identified several likely contributing factors. Advertisement They include the general loss of open spaces that mean fewer flowers and leaves for food, as well as changing agricultural practices that have reduced the number of butterfly-friendly plants along the edges of crop fields. The growing use of pesticides by farmers and home gardeners probably plays a role. So does climate change, which produces higher temperatures that can dry plants out and make them inedible. “There is not one cause for the butterfly decline — that’s not how population extinction happens,” Forister said. “It’s more likely a suite of factors that are pushing on all these species.” Even the painted ladies (Vanessa cardui) appeared to be suffering as recently as last year. In 2018, Shapiro counted just 27 of the butterflies at the 10 sites he monitors on a regular basis. A year earlier, that number was 512 . Scientists say the reason for this year’s rebound can be summed up in one word: rain. And more specifically, rain in the desert. Advertisement “The more plants, the more butterflies,” Shapiro said. “So any year you have a real big bloom in the desert is potentially a big year for painted ladies.” People walk among wildflowers in bloom near Borrego Springs on March 6, 2019. Heavy winter rains produced more vegetation, which butterflies need to thrive. (Gregory Bull / Associated Press) The life cycle of these hardy butterflies is still a bit fuzzy, but scientists believe that each winter the entire Western population retreats to the California desert to wait for the rains to come. “Once it rains, and the plants start to germinate, they breed like crazy,” Shapiro said. “So where it rains is where they breed.” Advertisement This winter, the rains fell long and hard. “The average annual rainfall in the Coachella Valley is 3 inches,” Danoff-Burg said. ”This year, we had 3½ inches on Valentine’s Day alone.” Butterflies lay their eggs on plants so that the larvae will have something to eat after they hatch. All the rain produced an abundance of vegetation in the desert, which gave painted lady caterpillars plenty of food to munch on, scientists said. As a result, far more caterpillars than usual were able to survive into adulthood. Advertisement “The conditions were perfect for them, so now we are seeing a lot of them coming out all at once,” said Doug Yanega, a scientist at the Entomology Research Museum at UC Riverside. About 1 billion butterflies, known as Painted Ladies, are flying north from the deserts of Mexico to reach breeding grounds in Oregon. Who has seen these Painted Ladies in LA? 🦋 pic.twitter.com/mHZAnBOkeS — K-EARTH 101 (@kearth101) March 12, 2019 Even before the rains, painted ladies were not high on the list of butterfly species to fret about, Forister said. Vanessa cardui is the most abundant butterfly in the world and can be found on every continent except South America and Antarctica. “They are a boom-bust species,” he said. “In some ways, they are the most successful butterflies on the planet.” Advertisement Among their many superpowers is the ability to eat a remarkably wide range of plants. Most butterfly species rely on only one or two plants. Think monarchs and milkweed: If the number of milkweed plants drops, the number of monarchs will drop as well. Painted ladies generally stick to nettles, mallows and borages, but in a breakout year such as this, they will happily consume lupine, sunflowers and other types of plants. “They are able to ingest an amazing diversity of plant toxins,” Forister said. “Most insects can’t do that.” Unlike other species, they have the ability to shiver for warmth, allowing them to survive in cooler temperatures. Advertisement They’re also capable of flying great distances to find places to breed and lay their eggs. Scientists recently discovered that some painted ladies fly 2,500 miles across the Sahara each spring. After the butterflies reach adulthood in the California deserts, in late winter or early spring, they disperse to the northwest, flying without stopping at speeds of up to 25 mph. The insects can travel 240 miles from Lone Pine in the Eastern Sierra to Davis in three days. “They fly like a bat out of hell,” Shapiro said. The migrating painted ladies are fueled by a packet of yellow abdominal fat, stored from their caterpillar days, that enables them to fly hundreds of miles without stopping. (That fat is responsible for the yellow streaks on your car windshield if you happen to run into one.) When the fat reserve runs out, they will stop and breed. The next generation will continue the trek north. Advertisement<doc-sep>
The skies of Southern California have become filled with millions of painted lady butterflies in the biggest migration event since 2005, thanks to recent heavy rain. Experts say the state's unusually wet winter and cooler than normal February have enabled plants to flourish in a rare super bloom event, which in turn has provided plentiful food for butterflies. "The more plants, the more butterflies," Art Shapiro, a professor at the University of California, Davis's Department of Evolution and Ecology, College of Biological Sciences, told the Los Angeles Times. "So any year you have a real big bloom in the desert is potentially a big year for painted ladies." Shapiro told NBC the migration is the biggest since 2005. He estimates that billions of butterflies appeared during that migration. The Times reported that hundreds of the insects have been spotted in such locations as the 105 Freeway in Los Angeles. Also known as the Vanessa cardui, the medium-sized insects are known for migrating long distances. They can be identified by their pale orange upper wings, which feature black tips with dots of white. Their undersides are pale and emblazoned with peacock feather-like blue eyespots. In the winter, painted ladies head to west Texas and northern Mexico, according to NBC. The eggs they lay turn into caterpillars and transform into butterflies, which head north until their fat reserves are spent before breeding. After reaching Northern California, those insects will breed, and their spawn will make the journey to the Pacific Northwest. But they haven't arrived yet, Shapiro, who is based in Sacramento, told NBC. However, he has been notified of swarms in the city of Temecula and Anza-Borrego Desert State Park; to the north and east of San Diego, respectively and further north in the Coachella Valley and in Pasadena, just outside of Los Angeles. Doug Yanega, senior museum scientist at UC Riverside's Entomology Research Museum, told Los Angeles Curbed there are currently caterpillars "everywhere" in southern California's deserts. And he and his colleagues counted at least 100 butterflies in one minute during their lunch break at the institution, which is in the south of the state. He told Newsweek: "Millions came northward from Mexico, and now, after one generation, they certainly number in the billions." "Anecdotally, long-term resident entomologists I know are saying it's been about 20 years or so since they've seen such numbers." Because it can take about one month for caterpillars to turn into butterflies, the sightings could continue for up to three months, Yanega said. Excited locals have shared footage on social media of the butterflies taking to the skies. There are about 1 billion Painted Lady butterflies migrating from Mexico to Oregon, just now passing through SoCal. This was 25seconds I stopped to video. pic.twitter.com/xVUsrefBZB — Kathy P (@KKPofCC78) March 12, 2019 James Danoff-Burg, the conservation director at the Living Desert Zoo and Gardens in Palm Desert, told the Los Angeles Times he encountered a kaleidoscope of butterflies while he was riding his bike in the resort city of La Quinta in Riverside County. "They were flying parallel to me, just bobbing along as I rode past the date palms," he said. "It was absolutely magical. I felt like a Disney princess." Yanega told Newsweek the phenomenon is "one of the few 'worry-free' examples of animal population outbreaks in nature." "They are a native species (not exotic, like Gypsy moths in the Northeast), and—despite their broad diet—they almost never feed on commercial crops, so they're not a pest. It's hard to think of many other cases where an animal population can attain such numbers and not have a major negative impact on either the ecosystem or on humans, especially agriculture. "Essentially, the ecosystem is converting extra plant material (resulting from strong winter rains) into extra butterflies. Animals that feed on butterflies will benefit, while we get to sit back and enjoy the show." The scenes come as experts lament the decline of California's butterfly populations in recent decades. "It was a terrible—perhaps even catastrophic—butterfly year at all elevations, and no, we don't know why," Shapiro wrote in a report about 2018. This article has been updated with comment from Doug Yanega.