PHOTO PROVIDED A monarch butterfly is pictured. The monarch butterfly’s population has declined in recent years.

On July 13, I saw my first monarch butterfly of the year. This was the latest I ever recorded a sighting of the monarch butterfly. During the 1980s and 90s, I always wrote that I had my first monarch sighting in June.

The monarch population has been on a steep decline. According to newly released data on wintering sites in Mexico, the population of monarch butterflies decreased by 26% over last winter. The report on February 25 stated the overall eastern monarchs have declined by more than 80% over the past two decades.

A 2017 study by Washington State University researchers predicted that if the monarch population dropped below 30,000, the species would likely go extinct in the next few decades, without a plan to save them.

Researchers state that climate change and farming practices have been a few of the reasons the monarch is threatened with extinction. The springtime weather delaying the blossoming of wildflowers has been disrupting the annual 3,000-mile migration. Spring weather, especially in Texas, is important for providing the monarch butterfly’s first generation to lay eggs. From these eggs, caterpillars hatch, grow and become butterflies. These butterflies continue the trip north to Canada. The spring of 2021 brought Texas some of the lowest temperatures ever recorded for that area. This cold spell was very hard on the caterpillars.

The eastern monarch population is made up of the butterflies east of the Rocky Mountains and accounts for roughly 99% of all North American monarchs. They migrate each winter to fir forests on high-elevation mountaintops in central Mexico. Scientists estimate the population size by measuring the area of trees turned orange by the clustering butterflies. That population has been dangerously low since 2008.

In 2021, the number of western monarch butterflies wintering along the California coast has also plummeted to a record low, putting the orange-and-black insects closer to extinction. The annual winter count by the Xerces Society recorded fewer than 2,000 butterflies. This was a massive decline from the tens of thousands tallied in recent years and the millions that clustered in trees from Northern California’s Marin County to San Diego County, in the south, during the 1980s.

Western monarch butterflies head south from the Pacific Northwest to California each winter, returning to the same places and even the same trees, where they cluster to keep warm. The monarchs generally arrive in California at the beginning of November, and their spring northward migration begins in March.

On the eastern side of the Rocky Mountains, the monarch population travels from southern Canada and the northeastern United States across thousands of miles to spend the winter in Central Mexico.

Scientists estimate the monarch population in the eastern United States has fallen approximately 80% since the mid-1990s; however, the drop-off in the western United States has been even steeper.

The Xerces Society, which is a nonprofit environmental organization that focuses on the conservation of invertebrates, recorded approximately 29,000 butterflies in its annual 2021 winter survey. This was not much different than the tally for the 2020 winter when an all-time low of 27,000 monarchs were counted.

The count this year is dismal. At iconic monarch wintering sites located in the city of Pacific Grove, volunteers didn’t see a single butterfly.

Other well-known locations — such as Pismo State Beach, Monarch Butterfly Grove and Natural Bridges State Park — which normally host thousands of butterflies, only hosted a few hundred butterflies. Sarina Jepsen, Director of Endangered Species at the Xerces Society, reported that their absence this year was heartbreaking for volunteers and visitors flocking to these locales sites hoping to catch a glimpse of the awe-inspiring clusters of monarch butterflies,

The monarch butterfly will only lay its eggs on the milkweed plant. Scientists say the butterflies are at critically low levels in western states due to destruction of the milkweed habitat along migratory routes as housing expands into their territory and also increased use of pesticides and herbicides.

Next week’s article? The butterfly itself.

Bill Bower is a retired Pennsylvania Game Commission Wildlife Officer. Read his blog and listen to his podcasts on the outdoors at www.onemaningreen.com.