Monarchs - The Cockroach Of Butterflies

By Amy Buskey

Part 2 of a 2-part series

We certainly don’t think of cockroaches when we envision a Monarch butterfly, but there are solid facts that make monarchs just as resilient. In our first look at Monarchs (September, 2021/GOT MILKWEED?), the grim facts of their steep decline is sobering. It is well documented that the eastern population has declined over 80% in the last two decades. But for the western Monarchs, the decline is downright staggering at 99.9%%. The population, counted by citizen scientists at Monarch overwintering locations in southern California dropped from around 300,000 three years ago to just 1,914 in 2020. However, last winter large numbers of Monarchs were found in San Francisco and Los Angeles - two areas that had not seen winter breeding of Monarchs prior to 2021. 

What exactly does this mean? Professor David James (Washington State University’s Department of Entomology) explains, “There’s more to it than just counting overwintering butterflies,” James said. “It seems that Monarchs are evolving or adapting, likely to the changing climate, by changing their breeding patterns.” The huge numbers of Monarch caterpillars in the Bay area indicates these populations are breeding, just in different areas than in the past - a very hopeful sign for their future. Professor James recalls a similar scenario that played out decades ago in Sydney, Australia, while working there on his Ph.D. dissertation. “In Australia, Monarchs haven’t gone extinct,” James said. “They’ve just adapted and moved along with a smaller population. And there’s no effort to preserve them there because they aren’t a native species. They’re just very resilient.” 

While the declining numbers of Monarchs in both the western and eastern U.S. are certainly reason for concern, James believes there will be a plateau for the species, but not extinction. “San Francisco is very similar, climate-wise, to the area around Sydney,” James said. “And seeing this winter breeding, which is something new we saw in Australia in the late 1970s, leads me to think that Monarchs will adapt well to the changing climate in the western US.” James is continuing his long-running Monarch tagging program where citizen-scientists like myself raise, tag, and release Monarchs so they can migrate south for the winter. Similar to the eastern monarch tagging program (https://monarchwatch.org/tagging/), James believes more tagged butterflies will be found around the Bay area this coming winter in breeding, instead of non-breeding overwintering colonies. 

But more work with citizen-scientists is needed to arrive at solid scientific conclusions. “We don’t know if this adaptation will continue and how successful it will be,” James   said. “The western Monarch population is quite precarious right now. It’s at a tipping point, and something is happening. We need to do more work to find out exactly what is happening.” 

One factor scientists continue to point to for declining populations is habitat loss - both here and in Sydney. It is likely a combination of factors, including pesticides, climate change, and loss of habitat that has their numbers falling. Whatever the case may be, one of the easiest things we can do to plan for the monarchs’ future is to plant their host food - milkweed. Even an area as small as 10 x 10 can provide food for a hundred or more Monarch caterpillars throughout the season. At the time of penning this article, my husband and I have now collected, raised, and released over 100 Monarchs - with a couple dozen more coming down the pike. The key to raising these beauties is to be sure you’ll have enough food for all the ‘cats’. 

As for tagging Monarchs, only the migrating generation - the butterflies of mid to late August and all of September in our area get stickered. What I had initially thought of as impossible - attaching a sticker to the wing of a Monarch, that is, has actually become secondhand. I simply reminded myself that I wasn’t tagging a shark, just a butterfly. The area to attach a tag to is specific, the discal cell, shaped like a mitten, and can be found on the base of the large wing. And you need not raise Monarchs in order to tag, you can tag wild specimens as well. All the information you need including ordering tags, tag recovery lists, and tag data submission can all be found here: https://monarchwatch.org/tagging/. Tags for this area (Massachusetts/Rhode Island) can be ordered in July, and are shipped after August 1 ahead of the migration times. Submitted tag information includes things like tag numbers, date of release, male or female, and location of release. 

Should you recover a tagged Monarch (dead or alive), or observe one that is tagged and are able to get a look at the tag number, go ahead and report it on the monarch watch site. Your submission, however insignificant it may seem, provides important information in migratory patterns to those collecting the data. In the meantime, and while the best time of year to plant is upon us, get your hands on swamp milkweed plants and get going on your future Monarch habitat. Their future is literally in our hands.

Amy Buskey, formerly of Norwood, resides in coastal Rhode Island with her husband Rick and their beagle, Doug. She can be reached at [email protected]