These butterflies are seen across the U.S. and southern Canada, with eastern and western populations divided by the Rocky Mountains. They are also widespread in Mexico and parts of Central and ...

Environmentalists say the population of monarch butterflies in North America has declined between 22% and 72% over 10 years, depending on the measurement method.

The number of monarch butterflies wintering in the mountains west of Mexico City, rebounded this year, doubling the area they covered in 2024 despite the stresses of climate change. The ...

Nonetheless, “when you think that there were three to 10 million butterflies in winter in the 1980s, and now there are 250,000,” she says, the overall trend in winter data is not promising.

Those east of the Rocky Mountains fly up ... In the late 1990s the clustered butterflies ... Giglio spends her free time in her yard, tending to coneflowers, lavender, zinnia, sunflowers, ...