Monarch butterfly populations in North America (2010s-2020s)
Eastern monarch butterfly populations in North America declined dramatically due to loss of milkweed habitat, pesticide use, and climate stress. Annual winter colony counts in Mexico fluctuated wildly, collapsing to some of the lowest recorded levels in 2013 and again in the early 2020s, then showing partial recoveries in wetter, favorable years.
The U.S. Fish and Wildlife Service proposed listing the monarch as threatened in 2024, and the species became a flagship for pollinator conservation.
The monarch's boom-and-bust cycle demonstrated that a charismatic migratory insect can capture public attention and drive conservation action, but recovery depends on sustained habitat restoration, not single favorable years.
Both species are migratory insects whose populations swing dramatically with weather and habitat conditions. The monarch's experience shows how a high-profile insect can rally conservation funding and policy attention — a pattern the bogong moth's 2026 return may replicate.