Monarchs clustering at Natural Bridges State Park, Santa Cruz, CA - November 2021
Those of you who read the news last year know that our western monarch population dipped to a dangerous level in 2020, indicating possible extinction of this population. Xerces Society for Invertebrate Conservation (Xerces) estimated the total population at just 1,914 during their annual Thanksgiving count. Images like the above clustering monarchs simply didn't happen last year. Zero monarchs were reported at several popular overwintering sites that draw tourists and locals alike. This was alarming and unprecedented.
Every one of us following this story has been nervously awaiting the numbers from this year's count. The preliminary counts are in and are shocking to say the least! Initial numbers reported indicate that there are around 200,000 monarchs in overwintering sites along the California coast! While this gives us hope and is really, REALLY promising news, we need to be cautiously optimistic and wait for a few more years of data to be sure this isn't a fluke. For now, however, we should all be using last year's dangerously low numbers to make changes that will help monarchs in the future so we never witness a that like that again.
Here are five steps we can all take going forward:
1) If you live either on the coast or inland, plant native plants that will not only help monarchs but other pollinators as well. Species that are most critical to monarchs should bloom in the early spring (February - April) to support spring migration our of California, as well as fall (October - November) when monarchs are returning to their overwintering grounds. If you live on the coast, you can also plant winter blooming natives for the monarchs to nectar on throughout the winter. Visit local nurseries that sell native plants, or request them if your local nursery does not carry them. If enough people demand them, they will almost certainly sell them.
2) If you live within 5-10 miles of the California coast, do not plant native or non native milkweed. This explanation comes directly from Xerces: Historic records suggest that milkweed was largely absent from most coastal areas of California. Because of the mild winter temperatures, milkweed planted close to the coast can often escape hard frosts--delaying or preventing these species from going dormant in the fall. This may disrupt the monarch’s natural cycle, encouraging them to continue to mate and lay eggs into the winter. This phenomenon is well-documented in non-native, tropical milkweed (A. curassavica) which stays evergreen and is associated with winter breeding in Florida, the Gulf Coast, and Southern California. And winter breeding has costs-- OE levels of winter breeding monarchs are 9 times the level of non-breeding, overwintering monarchs (Satterfield et al. 2016). In coastal California, even native species may act like tropical milkweed--staying green late into the fall-- and cause similar issues as tropical milkweed. For these reasons, the Xerces Society does not recommend planting milkweed (non-native or native) close to overwintering sites (within 5-10 miles of the coast) in Central and Northern coastal California where it did not occur historically.
3) If you live at least 5-10 miles away from the coast, plant native milkweed species only. Never plant tropical/Mexican milkweed (Asclepias curassavica - see paragraph above). You can request native milkweed from your local nursery while you're requesting native flowering plants (mentioned earlier)! If you are unable to find local milkweed species, you can purchase seeds from Xerces Milkweed Seed finder here...
4) NEVER use pesticides on your lawn or in your garden! Ever. Pesticides, particularly glyphosate, or round up (which is an herbicide), are devastating to monarchs, other insects, as well as humans. Glyphosate is used throughout the country to eliminate weeds in areas of agriculture. One weed that is particularly hard-hit is milkweed, the monarch butterfly's host plant. Without it, they are unable to complete their life cycle, resulting in loss of species throughout their migration route. Additionally, recent studies have shown that glyphosate wreaks havoc on our bodies by increasing the risk of cancer, causing endocrine-disruption, celiac disease, autism, effect on erythrocytes, leaky-gut syndrome and other issues. None of that sounds like something any of us wants, so just don't buy the stuff and you won't be tempted to use it. FYI: Glyphosate is banned in several European countries due to its affect on humans.
5) Support overwintering habitat conservation and restoration. Adopt an overwintering site and become involved in protecting and advocating for your site. Start by contacting your local officials and asking them to protect overwintering habitat in your area used by monarchs.
If you're lucky enough to live in an area where monarchs cluster during the winter, assume all vegetation on your property is necessary for this phenomenon, and please don't trim any trees or remove any vegetation. However, do feel free to plant native flowering plants for them to use during the winter months.
If we all do our part to help monarchs, they will thrive in the years to come. Hopefully some day we will look back at our efforts during this time and know we contributed to a conservation success, rather than being the cause of the unnecessary extinction of one of our most beloved species.
Monarch butterfly at Natural Bridges State Park, Santa Cruz, CA November 2021