Be on the lookout for migratory Monarch butterflies from the Pacific Northwest heading south to their overwintering sites along the California coast.
It's been a very good year for Monarchs in the Pacific Northwest (PNW), according to noted entomologist and Monarch researcher David James, an associate professor at Washington State University (WSU), Pullman.
"The numbers we are seeing in the PNW this summer are consistent with numbers I've seen in summers past when the overwintering population was approximately 250,000 as it was last winter," he wrote in an email Aug. 31.
"I have been compiling all the PNW monarch reports I have come across this summer--as I have done for many summers in the past. These have been from iNaturalist, Journey North, various Monarch Facebook pages and personal communications I get many people telling me they've seen a monarch. I verify all reports, that is, they must have a photo, or I know the reporter is experienced."
"Last summer (2021) I verified approximately 60 Monarch sightings in the PNW. This summer, I have had approximately 500 verified reports. "So, I think we have seen an 8-10 fold increase in Monarch numbers this summer in the PNW. The majority have been in Oregon, followed by Idaho, Washington and British Columbia. There are also positive reports of good numbers of Monarchs in Utah, Nevada and eastern California."
"So the signs are there for a good migration back to California this fall," James said. "The big question will be whether the migrants proceed normally to the overwintering sites or whether they do what they did in 2020, establish winter breeding populations in slightly inland places like San Francisco and Los Angeles. The determining factor will be the temperatures California experiences over the next six weeks. If average temperatures prevail, then the butterflies will go to the coastal overwintering sites and we will have--I think--spectacular numbers again...at least as high as last year and possibly much higher."
To track migratory Monarchs, citizen scientists in the David James' research program affix a tag on the discal cell (underside of the hind wing). The tag does not interfere with its flight.
This year James handed out 2000 tags to citizen scientists in southern Oregon.
One of his citizen scientists, Steve Anderson of Ashland, Ore., tagged a male Monarch on Aug. 28, 2016 that stopped for nectar in our Vacaville pollinator garden on Sept. 5, 2016. The tag read “Monarch@wsu.edu A6093." It hung around for five hours. (See Bug Squad blog and WSU news story)
"So, assuming it didn't travel much on the day you saw it, it flew 285 miles in 7 days or about 40.7 miles per day," James told us back in 2016. "Pretty amazing. So, I doubt he broke his journey for much more than the five hours you watched him--he could be 100 miles further south by now."
This year, to date, we have not seen a single Monarch in our pollinator garden. James estimates we will start seeing the first ones within the next few weeks. "Johnson has already had one of his tagged monarchs recovered, admittedly only a few miles away but it was heading south!"
Butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology, spotted four within half an hour in the UC Davis Arboretum and Public Garden on Aug. 26. One was a tattered male. (See Bug Squad blog)
What to do if you see a WSU-tagged Monarch? Photograph it, if you can, and contact David James at email@example.com or the PNW Facebook page. Also, report any Monarch sightings to iNaturalist and Journey North.
Meanwhile, Monarch scientists, citizen scientists and Monarch enthusiasts are looking forward to the 2023 International Western Monarch Summit, set Friday through Sunday, Jan. 20-22 at Pismo Beach, San Luis Obispo. Registration is now underway. It's sponsored by Western Monarch Advocates (WMA), which relates its mission is "to serve as an overarching entity to encourage and facilitate communication and interaction of groups and individuals committed to restoring the western monarch butterfly population-regardless of their affiliation or location--in the hope that the shared knowledge will empower each of them to improve and better achieve restoration goals within their own respective affiliation or location."
The International Union for the Conservation of Nature (IUCN) placed the migratory monarch butterfly on its Red List of threatened species on July 21, 2022, classifying it as endangered.
"In the 1990s, nearly 700 million monarchs made the epic flight each fall from the northern plains of the U.S. and Canada to sites in the oyamel fir forests north of Mexico City, and more than one million monarchs overwintered in forested groves on the California Coast," according to the Xerces Society for Invertebrate Conservation. "Now, researchers and citizen scientists estimate that only a fraction of the population remains, monarchs have declined by more than 80% since the 1990s from central Mexico, and by more than 99% since the 1980s in coastal California."
It's early spring and Western monarchs are heading inland from their overwintering sites along the California coast.
Have you seen any monarchs?
A group of monarch researchers from Washington State University, Tufts University, University of California at Santa Cruz, and the Xerces Society for Invertebrate Conservation seek your participation in the Western Monarch Mystery Challenge to help gain insight as to where the monarchs go. They want to fill "a critical gap in knowledge about habitat needs of migrating monarchs in the spring."
“We are very excited to see so many western monarchs on the coast this winter!" said conservation biologist and lead researcher Cheryl Schultz, a professor in Washington State University's School of Biological Sciences, in noting that the 2021 Thanksgiving count directed by the Xerces Society of Invertebrate Conservation totaled 247,237, a 100-fold increase from the less than 2000 monarchs recorded in 2020. "Monarchs are resilient. Because the numbers are up this year, it is a fabulous opportunity to learn where they go when they leave the coast as they head to breeding areas."
The challenge, launched Feb. 14 and to end April 22 (Earth Day), is a call to action: If you see a monarch in the area of California, Oregon, Washington, Nevada, Idaho and Utah (see map below), what you do is report the sighting, take an image (a cell phone photo is fine) and enter it the campaign for a chance at a prize.
While on sabbatical at UC Davis, Crone presented a seminar Jan. 29, 2020 to the Department of Entomology and Nematology on "Why Are Monarchs Declining in the West?"
“Surprisingly, we don't really know where western monarch butterflies are during this time period, roughly mid-February through mid-May," Crone told the UC Davis crowd. "Future research will focus on filling this knowledge gap, as well as building quantitative knowledge of the western monarch demography throughout their complex annual life cycle, which is needed to understand the relative contributions of habitat at different points in the life cycle to population declines and recovery.”
Crone related that what fascinates her about monarchs is "the possibility that we can recover the western monarch population from its recent steep decline to being abundant again. This should be a problem we can fix."
The Western Monarch Mystery Challenge "is an opportunity to get even more people to participate in western monarch community science–and these animals need our help right now, more than ever," said conservation biologist Emma Pelton of the Xerces Society.
"We know they spend winter months (November to February) in groves along the California Coast, and start breeding in central California in May," the group of researchers wrote in an email. "However, we know little about where monarchs are in March and April. Solving the mystery of where western monarchs spend the spring is central to conserving and restoring the phenomenon of monarch migration in the West."
The call to action, they said, is simple:
- If you see a monarch outside the overwintering groves, take a picture (don't worry, it can be blurry). We suspect that monarchs spend the spring somewhere between the coast and the Central Valley
- Report it to iNaturalist (the app is free) OR email it to firstname.lastname@example.org and include species, date and location
- Be automatically entered to win a variety of prizes every week you report a sighting. Be sure to check your messages on iNaturalist if you use the app to submit sightings. If you upload a monarch photo from outside the overwintering sites (and not any from monarch rearing projects as these "skew the data and could jeopardize the quality and legitimacy of conservation plans) you will automatically be entered in a weekly prize drawing. Prizes include gift cards to REI and other awards. More information is available at https://labs.wsu.edu/conservation-biology/western-monarch-mystery-challenge/
The Western Monarch Mystery Challenge is supported by the Monarch Joint Venture in collaboration with the Western Association of Fish and Wildlife Agencies, as part of its Western Monarch Conservation Plan, 2019-2069, a regional program to restore and recover monarch butterflies across the Western landscape.
"Guess, who's back?" has nothing to do with the catchphrases uttered by Arnold Schwarzenegger and Jack Nicholson. (Remember when Schwarzenegger promised "I'll be back!" in the 1984 science fiction film, The Terminator, and Nicholson vowed "I'm back" in the 1980 psychological horror film, The Shining?)
Monarch butterflies, Danaus plexippus. Well, at least one monarch is back in the area.
Shapiro sighted a female monarch today in West Sacramento, Yolo County. "It was in good shape, not looking stressed. Of course, Asclepias (native milkweed) has not broken ground."
It's an early sighting, which probably means the coastal clusters may be breaking up early due to the warmer weather than usual.
Shapiro, who maintains a research website at http://butterfly.ucdavis.edu/, has monitored butterfly population trends on a transect across central California since 1972. The 10 sites stretch from the Sacramento River Delta through the Sacramento Valley and Sierra Nevada mountains to the high desert of the Western Great Basin.
The previous plexippus he's seen before Feb. 10 include:
- Jan. 29, 2020 (See Bug Squad blog)
- Feb.1, 2014
- Feb. 9, 2006
- Feb. 9, 1976
"And lots in February after the 10th."
Meanwhile, most of the 250,000 monarchs tallied in California during the Thankgsiving Count, directed by the Xerces Society of Invertebrate Conservation, are still overwintering. Note that this is a 100-fold increase from the 2020 Thanksgiving Count when Xerces recorded a mere 2000.
Western monarchs generally begin clustering at their overwintering sites along coastal California in the late fall, peaking in size in late November or early December. Mating season usually begins around Valentine's Day. The monarchs traditionally depart their overwintering sites in late February or the beginning of March and head inward.
"Insect populations are well known for large annual fluctuations in size. However, rarely do these fluctuations occur on the scale currently being seen in western monarchs. From less than 2,000 monarchs counted in 2020, we currently have more than an estimated 200,000 at the overwintering sites! A 100-fold increase! This is staggering! However, it is less of a surprise to me than many others. In March 2021, I published a commentary paper titled Western North American Monarchs: Spiraling into Oblivion or Adapting to a Changing Environment? (Animal Migration journal). I suggested the latter was the case and stated: ‘the adaptability of the monarch butterfly will allow it to persist in a changed environment'. I based this on more than 40 years study of monarch populations, particularly research I did, published in peer-reviewed journals, that showed monarchs in Australia (they arrived in 1870 by island-hopping across the Pacific) had adapted physiologically to Australian conditions. I think we are seeing this monarch ‘power' now. They are trying different things in terms of life strategies and inevitably there will be failures and successes. This is how insects adapt and evolve. We will see more ups and downs in the future, but I have seen how adaptive and resilient the monarch is. This isn't to say we shouldn't help the monarch. We should and we are, primarily by creating habitat and reducing pesticide use. We can work with the adaptable and resilient monarch and ultimately turn 200,000 into 2,000,000!"
Mona Miller, who administers the popular Facebook page, Creating Habitat For Butterflies, Moths, & Pollinators, responded to the WSU post: "Monarch are resilient insects, they have so many strategies to increase their population, but they do have their limits. We must stop pulling out tropical milkweed and cutting it back. Washing off all milkweed should suffice to clean off the OE spores. I emailed several scientists, no one could tell me that OE (Ophryocystis elektroscirrha is a protozoan parasite) has any way to attach to milkweed leaves other than getting caught in the hairs. Tropical milkweed has smooth leaves. Tropical milkweed has been in California since 1909, that is over 100 years. Totally eradicating tropical milkweed just like totally eradicating all the eucalyptus trees would have a detrimental effect on the Monarch population, perhaps it already has." (Note: both eucalyptus trees and tropical milkweed are non-natives.)
"Do plant native milkweeds and nectar sources," she advocates. "If you don't have land, plant these plants in containers. Any habitat is critical to help feed the pollinators including Monarch butterflies."
In response to a post that "Tropical milkweed and eucalyptus trees are not native to Ca regardless of how long they have been here," Miller pointed out: "There are many plants growing in California that are not native to California. The fact is that the Monarch butterflies are using both of these plants. If these plants are immediately eradicated it would be compromising shelter, nectar, and host plants for the Monarch butterfly. During the winter both are blooming and provide nectar. Cutting back tropical milkweed when it has caterpillars in the winter should not be done. How is the Monarch butterfly going to evolve to adapt to the weather without tropical milkweed? Like I said, just wash off all milkweeds to clean off the OE. Due to changes in weather, there are also some native milkweeds that are not dying back in the winter. We can help the Monarch butterflies adapt or we can pull the rug out from under them by continuing to eradicate the plants that they need for winter survival."
Another point: Monarchs aren't native, either. Read Lincoln Brower's "Understanding and Misunderstanding the Migration of the Monarch Butterfly (Nymphalidae) in North America: 1857-1995" (Journal of the Lepidopterists' Society 49(4), 1995,304-385.) It begins: "Since 1857, amateurs and professionals have woven a rich tapestry of biological information about the monarch butterfly's migration in North America. Huge fall migrations were first noted in the midwestern states, and then eastward to the Atlantic coast. Plowing of the prairies together with clearing of the eastern forests promoted the growth of the milkweed, Asclepias syriaca, and probably extended the center of breeding from the prairie states into the Great Lakes region. Discovery of overwintering sites along the California coast in 1881 and the failure to find consistent overwintering areas in the east confused everyone for nearly a century. Where did the millions of monarchs migrating southward east of the Rocky Mountains spend the winter before their spring remigration back in to the eastern United States and southern Canada? Through most of the 20th century, the Gulf coast was assumed to be the wintering area, but recent studies rule this out because adults lack sufficient freezing resistance to survive the recurrent severe frosts."
Art Shapiro, UC Davis distinguished professor of evolution and ecology who maintains a research website at http://butterfly.ucdavis.edu/, weighed in on the issue today in an email about the monarch population increase: "We do not know where they are coming from. This merely goes to show (1) how spotty our coverage is. (2) how little we understand about life-history plasticity in this species. (3) that most of the received wisdom about the decline and its causes is bunk."
Shapiro has monitored butterfly population trends on a transect across central California since 1972. The 10 sites stretch from the Sacramento River Delta through the Sacramento Valley and Sierra Nevada mountains to the high desert of the Western Great Basin. The largest and oldest database in North America, it was recently cited by British conservation biologist Chris Thomas in a worldwide study of insect biomass.
We remember when Shapiro observed an way-early monarch in Sacramento on Jan. 29, 2020. Later in the afternoon, he heard monarch scientist Elizabeth Crone, professor of Tufts University, present a UC Davis Department of Entomology and Nematology seminar on the decline of Western monarchs.
In her seminar, Crone expressed concern about the lack of scientific knowledge about monarchs, especially when they emerge from their overwintering sites along coastal California, usually around February, and head inland. Said Crone: "We don't know what they're doing between February and when milkweeds break ground later in spring."
There is so much we do not know about monarchs...
UC Davis-affiliated resource, published Nov. 17, 2020 in Proceedings of the National Academy of Sciences (PNAS):
"Two Centuries of Monarch Butterfly Collections Reveal Contrasting Effects of Range Expansion and Migration Loss"
It's one of the highest honors a scientist can receive. Members are elected to NAS in recognition of their distinguished and continuing achievements in original research.
Agrawal received his doctorate in population biology in 1999 from UC Davis, working with major professor Richard "Rick" Karban, UC Davis Department of Entomology and Nematology.
"Anurag is an inspiration as a scientist and as a person," Karban said. "I've learned a lot from him."
At Cornell, Agrawal is the James A. Perkins Professor of Environmental Studies in the College of Agriculture and Life Sciences. He researches the ecology and evolution of interactions between wild plants and their insect pests, including aspects of community interactions, chemical ecology, coevolution and the life cycle of the monarch butterfly.
Agrawal is the author of the celebrated book, Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution, published in 2017 by Princeton University Press. The book won a 2017 National Outdoor Book Award in Nature and Environment and an award of excellence in gardening and gardens from the Council of Botanical and Horticultural Libraries. It was also named one of Forbes.com's 10 best biology books of 2017. Read a review of his Monarchs and Milkweed book from the journal Ecology and read the first chapter here. (You can order the book here.)
As Agrawal said in a Cornell news release, “It's a tremendous honor and totally unexpected. I look forward to representing Cornell and also playing a part in the NAS role of advising the U.S. government on science policy.”
"A key research focus for Agrawal's Phytophagy Lab is the generally antagonistic interactions between plants and insect herbivores," according to the Cornell news release. In an attempt to understand the complexity of communitywide interactions, questions include: What ecological factors allow the coexistence of similar species? And what evolutionary factors led to the diversification of species? Agrawal's group is currently focused on three major projects: the community and evolutionary ecology of plant-herbivore relationships; factors that make non-native plants successful invaders; and novel opportunities for pest management of potatoes. Recent work on toxin sequestration in monarch butterflies was featured on the cover of the April 20 issue of Proceedings of the National Academy of Sciences."
Agrawal holds two degrees from the University of Pennsylvania, a bachelor's degree in biology and a master's degree in conservation biology. He joined the Cornell faculty in 2004 as an assistant professor of ecology and evolutionary biology, with a joint appointment in the Department of Entomology. He advanced to associate professor in 2005, and to full professor in 2010. He was named the James A. Perkins Professor of Environmental Studies in 2017.
A fellow of the American Association for the Advancement of Science (2012), and recipient of the American Society of Naturalist's E.O. Wilson Award in 2019, Agrawal won the Entomological Society of America's 2013 Founders' Memorial Award and delivered the lecture on Dame Miriam Rothschild (1908-2005) at ESA's 61st annual meeting, held in Austin, Texas.
Agrawal was at UC Davis in January of 2012 to present a seminar on "Evolutionary Ecology of Plant Defenses." His abstract: "In order to address coevolutionary interactions between milkweeds and their root feeding four-eyed beetles, I will present data on reciprocity, fitness tradeoffs, specialization and the genetics of adaptation. In addition to wonderful natural history, this work sheds light on long-standing theory about how antagonistic interactions proceed in ecological and evolutionary time."
Members are elected to NAS in recognition of their distinguished and continuing achievements in original research. Among those previously elected to NAS: Bruce Hammock, UC Davis distinguished professor of entomology who holds a joint appointment with the UC Davis Comprehensive Cancer Center. He was elected to NAS in 1999.