The California overwintering population has been reduced to less than 0.5% of its historical size, and has declined by 86% compared to 2017.

A study in Biological Conservation led by a WSU scientist documents the steep decline of monarch butterflies in the West. They could be functionally extinct within a few decades.

Rare monarch caterpillar-butterfly (Danaus plexippus) seen in five years.

8-10-14 Thousands of caterpillars - Lake Clark National Park, Alaska, USA