By Elizabeth Taylor
Spotting a beautiful monarch butterfly in our gardens or when hiking on a Douglas County Open Space is a special experience that all of us enjoy. The monarchs we are privileged to see in our region are part of the eastern population, those monarchs found east of the Rockies. A smaller population is found west of the Rockies, and both populations have among the most remarkable migration patterns on earth.
Monarchs in the eastern population go through several generations as they migrate north from their overwintering locations in Mexico each year. The monarchs seen along the Front Range in late spring are usually considered the second generation. As the monarchs continue migrating north, a third generation is born and then a final generation. Monarchs can be seen passing through our region again in September and October as the final generation migrates for thousands of miles on their remarkable flights to the overwintering grounds in the mountains of central Mexico. This generation remains in Mexico for several months over winter before starting the cycle again.
Two of our Douglas Land Conservancy volunteers, Curt Frankenfeld and Elizabeth Taylor, recently returned from a “Reefs and Rockies,” Denver Audubon sponsored trip to Mexico, where they visited the Monarch Butterfly Biosphere Reserve, high up in the Sierra Madre northwest of Mexico City. After climbing to several high altitude monarch sanctuaries on horseback or on foot, they observed millions of monarch butterflies clustered to stay warm on oyamel fir trees in the cool of the morning. Then as temperatures warmed up, they witnessed huge numbers of butterflies in flight. Curt and Elizabeth said that this was one of the most awesome experiences they have ever had. In addition, they noted some good news–the number of butterflies overwintering at these sanctuaries this year is almost double the disappointing number in 2024. However, that does not make up for the overall, longer-term, decline in the monarch butterfly population.
Unfortunately, monarch butterfly populations have drastically declined due to habitat loss, pesticide use, and changing climactic conditions. Although population numbers are variable from year to year, the eastern monarch population has decreased over 80% during the past three decades according to the Xerces Society. The western population has declined even more drastically. The U.S. Fish and Wildlife Service has proposed listing the monarch butterfly as threatened under the Endangered Species Act, but the decision has been delayed. However, monarchs are classified as endangered by the International Union for Conservation of Nature (IUCN) and Canada.
So what can we do to help? Migrating monarch butterflies look for flowers, especially native wildflowers, for nectar. As a result, they find wildflower pollinator gardens especially attractive. Planting wildflowers near your home or supporting pollinator gardens planted by various organizations in our area is one way that you can help. In addition, monarchs lay their eggs exclusively on milkweed plants, usually on the underside of leaves. Monarch caterpillars require milkweed leaves as their only source of food, making native milkweed plants a critical factor in the success of monarch populations. Planting even a few milkweed plants in your yard or garden can make a difference. When considering which species of milkweed to plant, select species native to our region of Colorado. Two species native to Douglas County and found on Douglas County Open Spaces are butterfly milkweed (Asclepias tuberosa) and showy milkweed (Asclepias tuberosa).These species are commonly available as seeds or starter plants at local nurseries. In addition, Elizabeth, who claims not to have a green thumb, notes that even she can grow these milkweeds, because once these perennials are started, they require very little maintenance. Other milkweed species are available, but be sure they are native to Colorado and suitable for your growing conditions. Above all, do not plant tropical milkweeds that are available from some nurseries, because they may do more harm to monarch butterflies than good.
Perhaps next summer, the answer to “Where are the Monarch Butterflies?” could be, “In my garden.”