The colourfully winged insects that travel vast distances over the course of generations have been closely watched in California since they neared extinction just three years ago.
The sight provided a bit of reassurance for Ms Stephanie Turcotte Edenholm, who counted more than a thousand monarchs at a sanctuary in the California coastal town of Pacific Grove. She worried, too, that they would mate and the females would fly off in search of milkweed plants to lay eggs on. Milkweed is all that baby caterpillars eat once the eggs hatch, but it was too early in winter for the plants to be growing.
The monarch was added in 2022 to the International Union for Conservation of Nature’s Red List of threatened species, and Xerces has asked the US Fish and Wildlife Service to place monarchs on its endangered list. The question of whether to protect monarchs is a philosophical one, since the insects are known more for incredible migrations than being crucial for pollinating crops or flowers, according to Xerces biologist Emma Pelton.
Some species of monarchs travel thousands of kilometres, from Canada to Mexico, while the lifespan of any single butterfly is typically measured in weeks.“It was kind of a magical thing to be immersed in the abundance of the natural world,” said Mr Henry, now director of Groundswell Coastal Ecology group in Santa Cruz, not far from Pacific Grove.Flourishing monarchs are also a sign of enough milkweed and habitat along the long migration corridor, Mr Henry said.