Monarch butterflies gather the souls of warriors who died in battle, and the souls of women who die in childbirth, and carry them to their final resting place.

Another ancient Aztec legend says that the Monarch butterflies are the souls of children who have died and come back. Interestingly, butterflies begin to arrive in Mexico by the millions on their annual migration south on November 2nd, the day celebrated as Dia de los Muertos or Day of the Dead.

Still other legends tell how a group of indigenous people migrated from the Rocky Mountains to central Mexico. Due to the intense cold the children and the elderly could not continue the trip and were left behind. To protect themselves from the cold they covered themselves with tree resin and pollen. Seeing them, their god took pity on them and turned them into butterflies so that they could continue their journey and find their families. The fir forests of Estado de Mexico and Michoacán came to represent the parents who waited for them with open arms. The name given to the Monarch Butterfly by the Mazahuas people of the Michoacán area of Mexico means Daughter of the Sun.

200 million butterflies will embark on their 2,800 mile annual journey this year from Canada and the eastern United States to the 10,000' high mountain forests that span the area between the Mexican states of Michoacán and Estado de Mexico. Oak, pine, and oyamel trees will be completely covered in orange with branches bending under the shear weight of hundreds of thousands of butterflies clustered one atop another to stay warm.

When the temperatures are cold – especially early in the morning – they sleep in clusters and close their wings, so at first sight they almost appear like dry leaves on the trees. As the morning progresses and the warmth of the sun filters through the forest, they open their colorful wings and the sky is ablaze in orange as they swirl through the forest and begin their mating rituals.

But climate change is taking an enormous toll on the Monarch population. Monarch butterflies exist in a very narrow temperature range from about 55 degrees to the low 70's, and it is for this reason that they migrate south at the beginning of autumn as temperatures begin to fall. But because over 95 percent of the population migrate en masse to a few patches of Mexican forest, each smaller than half a football field, a single storm or heat wave could effectively kill off the population. An early winter storm in 2002 killed an estimated 75% of the Monarchs, and again in 2012 a heatwave in the mid-west killed tens of thousands.

Monarch butterflies rely on the milkweed plant for survival. It is their only source of food, it is where they mate, and they lay their eggs on its leaves. But climate change is destroying milkweed and what isn't decimated by the weather is being systematically destroyed by ranchers, farmers, and developers. Milkweed is poisonous to cattle (and most species) and as cattle ranges expand these plants are rapidly disappearing, and as development encroaches the widespread spraying of weed killer on the fields is destroying the Monarch's natural habitat. The U.S. Fish and Wildlife Service estimates that between 1990 and 2015 one billion Monarch Butterflies vanished. It has been estimated that within 20 to 30 years the Monarch Butterfly will cease to exist.

For centuries butterflies have been thought of as magical and mystical things, fleeting apparitions from a childhood dream or a nearly forgotten fairytale, appearing unexpectedly on a summer's morning, then disappearing without a trace. To stand now, deep in a Mexican forest as the sun filters through the trees, and watch in utter silence as enormous branches bend and sway and suddenly come to life filling the sky in a burst of weightless orange, is to walk into a dream. I watch with the same wonder that I had as a child.

The United Nations reported last year that 1 million species of plants and animals face possible extinction due in large part to climate change. There have been five other mass extinctions on this planet in the past 450 million years and there is no rational reason to believe the extinction of the monarch butterfly is more critical than any of the others, but as Lierre Keith asks in her book Deep Green Resistance, “What is your personal carrying capacity for grief, rage, despair? We are living in a period of mass extinction. The numbers stand at 200 species a day. That's 73,000 a year, and there is no roll call on the nightly news.”