As they start to head south for the winter, monarch butterflies may find it's hard to go home again.

A winter habitat for the iconic orange, black, and yellow butterflies in Mexico is being chipped away by illegal logging, leaving less space for the millions of monarchs that will be fluttering down from the United States and Canada in the coming weeks.

A crackdown by Mexican authorities reduced illegal logging in the Piedra Herrada butterfly sanctuary northwest of Mexico City to zero by 2012, said Omar Vidal, director-general of the World Wildlife Fund's Mexico arm. But since then, logging has crept back into one of the communities surrounding the sanctuary, and aerial and satellite imagery documented 47 acres of trees cut down in the past year, Vidal told VICE News.

"There has been a tremendous effort by the community, the government, and other partners to stop the illegal activity, on the one hand by enforcement and on the other side by investing in the communities to develop sustainable communities," Vidal said. "But one of those communities didn't take care of their forest."

Logging can do great harm to the butterflies even when the fir trees in which they make their winter homes are spared. In 2002, a winter storm killed an estimated four-fifths of the 100 million butterflies wintering in Mexico, largely because the removal of trees made the insects more exposed to snow and freezing rain.

"Even though the actual trees that the monarchs are using are not being cut down, the adjacent illegal logging is having that ripple effect," David Mizejewski, a naturalist with the National Wildlife Federation, told VICE News.

"It's one of those complex scenarios where human populations are relatively poor and are just trying to make a buck and survive," Mizejewski said. "So there's this pressure on the landscape and the ecosystem that needs to be addressed as part of the conservation problem."

But as bad as the logging is, it's not the worst bit of lèse-majesteé the monarchs have had to tolerate. Years of plowing and pesticide use is killing the plant that feeds their caterpillars, fueling a plunge in monarch populations that has gone on for decades.

Milkweed is the only source of food for monarch larvae, and the butterflies lay their eggs in the plant, Mizejewski said.

"If milkweed goes away, the monarchs can't compete their life cycle and their population starts to plummet," he said. "That's what we're seeing here in their sort of breeding habitats here in the US."

In 1996, the US Fish and Wildlife Service estimated there were about 1 billion monarch butterflies across the United States. But that number has plunged by about 90 percent in recent years, the agency reported in early 2015. And while a lot of that is the result of natural grassland where milkweed once grew being converted to agriculture, a sizeable chunk of the responsibility can be laid in Americans' front yards.

"When it comes to how we manage the land in our cities and our towns and our front yards, we have this notion of what its supposed to look like — and that's usually a sterile, barren, giant expanse of lawn with maybe a few exotic plants," Mizejewski said. "We tend to be overzealous with moving and weeding and spraying, and what we have seen as a result of all of those things is that milkweed is not as abundant as it should be."

After sounding the alarm in February, the Fish and Wildlife Service poured a quick $2 million into conservation efforts, working with groups like the National Wildlife Federation. Environmental groups are urging Americans to plant more milkweed and preserve natural grassland in order to keep the butterflies in business.

"They're a species that so many people know and have grown up with in their backyards," Mizejewski said. "When we lose such an iconic species, it's a double whammy. It's not only bad for the ecosystem, but it takes something way from the beauty of the natural world, and that's something worth fighting for as well."

Meanwhile, back in Mexico, Vidal said the Michoacan state villagers who are cutting into the protected forest may be cutting into their long-term profits. Between 80,000 and 100,000 tourists visit the sanctuary every year, and logging means "losing the natural capital," he told VICE News.

Of the 32 communities surrounding the sanctuary, he said, only one is suspected of cutting into the forest. The rest "have clearly realized that it's better to protect the forest, because it's an investment for them and their children in the long run."