Entomologist David James of Washington State University, an authority on monarchs.

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."

This WSU-tagged monarch traveled from Ashland, Ore., to Vacaville, Calif., a distance of 285 miles in seven days, arriving in Vacaville on Sept. 5, 2016. (Photo by Kathy Keatley Garvey)

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 david_james@wsu.edu 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."

A male monarch nectaring on a Mexican sunflower, Tithonia rotundifola, on a warm sunny day in Vacaville, Calif. (Photo by Kathy Keatley Garvey)

Entomologist and monarch scientist David James of Washington State University posted this yesterday on his Facebook page, Monarch Butterflies in the Pacific Northwest:

"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" 

Let the count begin!

Researchers and volunteers in a three-week project headed by the Xerces Society for Invertebrate Conservation are now counting the Western monarch population at overwintering sites along the California coast.

It all began Saturday. An unofficial count estimates more than 50,000 monarchs are there. That's a huge increase from the fewer than 2000 tally last winter.

An Associated Press story this week indicated that the monarch population is "bouncing back."

Maybe "fluttering back?"

Since the 1980s, the Western monarch population, has declined by more than 99 percent, according to Xerces.  That led butterfly expert Art Shapiro, UC Davis distinguished professor of evolution and ecology who has monitored butterfly populations in Central California since 1972, to declare that the Western monarchs are on "life support."

Scientists blame the decline on habitat loss, pesticides and climate change. 

How many overwintering sites are there along the California coast? About 100. "One of the best-known wintering places is the Monarch Grove Sanctuary, a city-owned site in the coastal city of Pacific Grove, where last year no monarch butterflies showed up," the Associated Press reported.

"This year a preliminary count showed more than 13,000 monarchs have arrived at the site in Monterey County, clustering together on pine, cypress and eucalyptus trees and sparking hope among the grove's volunteers and visitors that the struggling insects can bounce back."

Monarch scientist David James, a Washington State University entomologist, recently presented a webinar on "Western Monarchs: Migration, Adaptation, Controversies and the Future" for the South West Monarch Study group.

"It was well-received but we had technical problems towards the end," he related on his Facebook page, Monarch Butterflies in the Pacific Northwest. "Gail Morris kindly allowed me to re-record it and you can now find it at the link below. My view of the future of western monarchs is more optimistic than some other monarch researchers. Much of this is based on my research on monarch physiology and ecology conducted 40+ years ago in Sydney, Australia, which showed monarchs well able to adapt to a different environment. I think we are seeing this now in the western US in real time! My thoughts on this are contained within the webinar. The recovery in population numbers at overwintering sites this fall, is not surprising to me but I am surprised at some of the large numbers coming in from various sites. I will take a look at some of the sites over the next few days and will report back here."

See James' presentation on YouTube at https://www.youtube.com/watch?v=g-hh5c8mw6o.