Data source:
Brower, L.P. et al., Decline of monarch butterflies overwintering in Mexico: is the migratory phenomenon at risk?
Insect Conservation and Diversity (2012),
5, 95-100. [1994-2011]
and
Rendon-Salinas, E. et al. Area of Forest Occupied by the Colonies of Monarch Butterflies in Mexico During the 2022-2023 Overwintering Period. [2012-2023],
Monarch Butterfly Numbers Are Down Sharply at Wintering Areas in Mexico by Catrin Einhorn for 2023-24.
Last updated 2024/02/08.
Video
Migratory monarch butterfly now Endangered - IUCN Red List (2022/07/27)
<><><> Fireflies <><><>
Are Fireflies Disappearing? Farmers' Almanac (2021/02/08)
<><><> North American Birds <><><>
Three billion North American birds have vanished since 1970 Science (2019/09/19)
<><><> Polar Bears <><><>
Are Polar Bears Endangered? Polar Bears International
<><><> Other Endangered Species <><><>
Endangered Species U.S. Fish & Wildlife Service