Every spring, Nicole Hamilton waits for the arrival of the monarch butterflies, those delicate, orange-and-black-winged creatures best known for their stunning annual migration, a journey of thousands of miles from Mexico to the United States.

And every year, she sees fewer of them.

Hamilton, president of the Loudoun Wildlife Conservancy, has been raising and releasing monarch butterflies for more than a dozen years. She keeps a journal to document the number of monarchs she sees each year, and as she saw her tally of local monarchs decline — from more than 100 in 2008 to about 55 last year, a pattern caused in part by the loss of the butterfly’s natural habitat in increasingly developed Northern Virginia — she decided it was time to take action.

“It really hit me, this epiphany. If we’re going to do something, we need to do it now,” she said.

This year, the Loudoun Wildlife Conservancy launched a campaign that aims to educate the community about the perils facing monarch butterflies and to help boost the number of monarchs in Loudoun by creating additional breeding and feeding sites here.

“People have asked me why should we care about the monarchs. Couldn’t we live without them?” Hamilton said. “I tell them yes, we could, but the monarch is really indicating something to us about our environment, whether it’s about climate change or our agricultural practices. The monarch is telling us something about what’s going on around us.”

Among the primary threats the monarchs face is the disappearance of milkweed plants, their breeding ground. Milkweed has become increasingly rare as the spread of genetically modified crops and the use of herbicide sprays transform the farmlands where the butterflies once thrived, particularly in the Midwest, according to experts.

Lincoln Brower, a biology research professor at Sweet Briar College in Virginia who has specialized in monarchs for more than 35 years, said the butterflies have suffered tremendously from agricultural practices and two other factors: new climate patterns and illegal logging in the forests of Mexico, where the monarchs spend the winter.

“Those three things have been pounding the monarchs for years,” Brower said. “The continued expansion of industrialized agriculture is going to have a major impact on the future of not only monarch butterflies, but all pollinating insects.”

Because more farms have turned to genetically modified crops and herbicide sprays that kill native plants, the insect food web “is unraveling,” Brower said. “It’s an incredibly serious problem. It’s an elimination of biodiversity on a scale that’s unprecedented.”

The butterflies are measured by the number of insects that are observed in an area of one square meter, or hectare, Brower said. Each hectare accounts for about 50 million butterflies. Last year, scientists documented more than two hectares of monarchs in Mexico. This year, the number was a little more than one hectare.

In the face of such a seemingly grim plight, the Loudoun Wildlife Conservancy’s efforts might seem too locally focused to have much effect, but the real value lies in spreading knowledge and awareness of the broader problem, Brower said.

“It’s about getting people interested and getting more kids involved,” he said. “If people plant a milkweed garden and a nectar garden, it’s not going to be the be-all and end-all of solving this problem, but the more people who get involved and care, eventually you can develop sufficient political clout to have some policy changes along the way.”

The Loudoun Wildlife Conservancy launched the campaign in January, but it has ramped up its efforts recently, as Loudoun residents have established more than 50 monarch way stations — gardens that serve as breeding and feeding sites for the butterflies — across the county. Schools, churches, residential communities and parks have taken part.

Each way station includes a mix of milkweed, the plants monarchs use for breeding, and nectar plants to nourish the young caterpillars when they hatch, Hamilton said.

The goal for the campaign was first intended to symbolically match the year: “We wanted to get at least 2,013 milkweed plants out there,” Hamilton said. So far, almost 2,500 have been planted across the county.

The campaign made donations of milkweed plants to 20 Loudoun public schools. The schools then conducted their own fundraisers to buy corresponding nectar plants, such as goldenrods and asters, Hamilton said.

At this point in the campaign, which will continue into early fall, when Loudoun residents who have helped raise caterpillars will come together to release the adult butterflies at local parks, the organization is focused on encouraging families to plant way stations and adopt the caterpillars, Hamilton said.

The first migrating butterflies arrived in Loudoun a week or two ago, she said, and are now laying their eggs. The adults will live for six to eight weeks, and their eggs will take about a month to develop into adult butterflies, she said.

“The end of our season here in Loudoun is about October 10,” she said, after which the new generation of insects will begin their long trek south. At the end of October, Hamilton said, the Loudoun Wildlife Conservancy plans to host a large celebration to conclude the campaign, “around the time that our monarchs will be arriving back in Mexico.”

And the group plans to launch the campaign again next year. The goal is to have the campaign continue and, the conservancy hopes, spread to neighboring areas of Virginia.

“When I first started this, I did get some questions from people saying, ‘What kind of difference do you think you can make?’ But it’s the idea of raindrops to puddles to rivers to oceans,” she said. “My garden is just a raindrop. But if I can encourage other people to do it too, then that becomes the puddle, and then the river, and it leads to this greater movement.”

People in Loudoun might not be able to solve the problem of herbicide sprays or illegal logging, she said, but there’s something that can be done about the loss of habitats because of development.

“That’s a suburban issue,” she said. “It’s one we can all solve here in our back yards. And if we all do it, then we can make a difference.”