Friends’ butterfly research has local, national implications

[L to R] Carol Blaney, Nancy Hamlett and Scott Marnoy, Claremont residents and Friends of the Claremont Hills Wilderness Park, partake in monarch and milkweed plant monitoring along Johnson’s Pasture on Tuesday. Hamlett points out to the group that an orange milkweed bug, Oncopeltus fasciatus, is feeding on the narrow-leaf milkweed in front of them. COURIER photo/Andrew Alonzo

by Andrew Alonzo |

Bright and early one recent Wednesday morning, two Friends of the Claremont Hills Wilderness Park members, Nancy Hamlett and Scott Marnoy, hiked north about a half mile into the park from Via Santa Catarina to gather data on monarch butterflies.

Around 7 a.m. the duo began performing routine work near Johnson’s Pasture, which included counting the monarchs that fluttered by.

“We’re monitoring the abundance of monarchs, milkweed [plants], and blooming plants in the park,” Hamlett said.

The monarch butterfly population is currently facing a decline across the United States, Marnoy said. Habitat loss, climate change, disease, pesticides, predation and human activities have, over the last two decades, caused the population to decline by about 70%, he added.

Hamlett and Marnoy spend about two hours a week monitoring the butterfly, insect and plant life in an area near Johnson’s Pasture.

In April 2022, the Friends of the CHWP joined a nationwide nonprofit group known as the Monarch Joint Venture. The organization, which is dedicated to conserving monarch butterflies across the United States, has the Friends of the CHWP keeping tabs on the monarch butterfly population in Claremont, as well as how the pollinator is engaging with its habitat.

The Friends of the CHWP is the only Los Angeles County-based group that is part of the Monarch Joint Venture. It uploads each week’s findings to the nonprofit’s monitoring application dubbed the “integrated monarch monitoring program,” or IMMP for short.

Friends of the CHWP has been monitoring the local monarch and milkweed population since April. The goal is to gather data to help the city with allocating grant funding or decision making for future wilderness park projects that could affect the monarch population.

“While monarchs and their caterpillars have been spotted on the milkweed, the extent to which the habitat supports monarchs is unknown,” Hamlett said in an email. “Understanding use of the habitat by monarchs will contribute both to a national understanding of monarch habitat and to future potential management actions in the CHWP.”

On Tuesday, Scott Marnoy, a member of the Friends of the Claremont Hills Wilderness Park, uses his magnifying glass to search a Woolley pod milkweed plant for signs of monarchs. Whether it’s the butterflies themselves, its larvae feeding on the nectar rich plant, or other insect-life, the Friends of the Claremont Hills Wilderness Park monitor and keep track of the Monarch and milkweed plants in and around Johnson’s Pasture. COURIER photo/Andrew Alonzo


Since the friends are part of the joint venture, the team utilizes IMMP for its local research.

“This information is vital to shaping our understanding of how monarchs interact with their environment, documenting conservation efforts, and tracking the population and its habitat as they change over time,” Hamlett wrote in an email. “Using their protocols means that data collected here will become part of a nationwide picture of monarchs and their habitat.”

In just over two months, Hamlett said the group has encountered and counted 14 adult monarchs as well as three larvae. In addition, the group has found that more than 500 milkweed plants — either woolly-pod or narrow-leaf milkweed — reside in the Johnson’s Pasture area.

But aside from all the counting, Hamlett explained what the friends look for during monarch monitoring hours.

“We record how many are there each time we sample, what plants they’re on, what times they’re here, what plants they like the nectar on, and if there’s a preference for which milkweed species [they like],” she said.

The data collected over the past two months will be used as benchmark info for future collections in Claremont. Eric Ey, the city’s human services supervisor, said that the goal of the project is to “really find some baseline data that we can incorporate into data that’s being collected nationwide to help make new decisions be made at the local, state and federal level even in order to help this species flourish.”

Asked why the work needed to be done, Hamlett replied, “Well I guess it depends on your definition of need.

“I mean you could just not do it. But if you want to find out and gather information both to help monarch conservation nationwide and to think about what would be appropriate future [land] management decisions in the park, we’re collecting data that would be useful for that.

Although not a monarch, a male checkered white butterfly (scientific name Pontia protodice) feeds on a Narrow leaf milkweed plant in Johnson’s Pasture along the Claremont Hills Wilderness Park on Tuesday. COURIER photo/Andrew Alonzo


Ey said one of the aims of the research is not only understand what’s going on in Claremont, but to use it to help paint that picture of what’s going on in California and nationwide.

“Especially as we see a decline in bees as well, making sure we have a sustainable habitat for all those pollinators is incredibly important,” Ey said.

“The fact is that as with all scientific research, progress is incremental,” Marnoy said. “Our small contribution is but one of many that will eventually paint a picture of what plants are exploited by monarchs, where these resources are found, and the distribution of monarchs across those assets.”

Although the Friends of CHWP is fairly new to the project, the idea to join has been gaining momentum since last year. The project began to generate steam when Hamlett and a few others began looking into grant funding to help preserve pollinating insects at the park.

Wondering if grant funds would be appropriate, in 2021 the Friends of CHWP began working with the city’s human services supervisor — not Ey but his predecessor. The group learned a lot about the requirements necessary for groups to be granted funds, one of which was monitoring pollinators’ habitat in the city.

Today, the Friends of the CHWP continue to help the city with resource preservation, park etiquette, and research and education in the park, Hamlett said. Aside from the monarch project, the friends also document plants and animals in the park, and host monthly volunteer events and opportunities for the community.

“We’ve been mapping invasive species in the park, with an eye of doing removal in the future,” Hamlett said.

Those interested in volunteering with the group for either the monarch project or others are encouraged to go to

For general information about the Claremont Hills Wilderness Park, visit


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