Monarch Population Status

The WWF-Telmex Telcel Foundation Alliance, in collaboration with the National Commission of Natural Protected Areas (CONANP), the National Autonomous University of Mexico (UNAM), and the Monarch Butterfly Biosphere Reserve (MBBR), announced the total forest area occupied by overwintering monarch colonies today. Nine (9) colonies were located this winter season with a total area of 0.90 hectares, a 59.3% decrease from the previous season (2.21 ha). This is the second lowest number counted to date – the lowest was 0.67 ha during the 2013–2014 overwintering season.

Figure 1. Total Area Occupied by Monarch Colonies at Overwintering Sites in Mexico.

Report: Areas of forest occupied by the colonies of monarch butterflies in Mexico, during the 2023-2024 overwintering period

WWF story: Eastern migratory monarch butterfly populations decrease by 59% in 2024

Note: The WWF-TELMEX Telcel Foundation Alliance collaborates with CONANP to systematically monitor the hibernation of the Monarch since 2004, and they join the Institute of Biology of the National Autonomous University of Mexico (UNAM) to analyze changes in forest cover in the area core of the Monarch Butterfly Biosphere Reserve in order to have scientific bases that support the implementation of conservation strategies for the benefit of the species, ecosystems and human beings.

MEDIA ADVISORY: Monarch Watch experts at KU available to discuss today’s announcement of low numbers in monarch butterfly population

Today authorities in Mexico City announced that the size of the eastern monarch butterfly population that overwinters in Mexico is the second smallest on record. The numbers are so low that few monarchs will be seen this coming summer in many parts of the U.S. and Canada.

WWF-Telmex Telcel Foundation Alliance, in collaboration with the National Commission of Natural Protected Areas (CONANP), the National Autonomous University of Mexico (UNAM), and the Monarch Butterfly Biosphere Reserve (MBBR), announced the total forest area occupied by overwintering monarch colonies as 0.90ha; a 59.3 percent decrease from the previous season (2.21ha).

This is the second lowest number of hectares counted to date. The lowest was 0.67 ha during the 2013–2014 overwintering season. A chart produced by Monarch Watch at the University of Kansas and posted to the Monarch Watch Blog shows the total forest area occupied by overwintering monarch colonies annually since the winter of 1994–1995.

Two Monarch Watch experts on the eastern monarch butterfly migration are available to discuss with reporters the low population numbers and their implications. Orley “Chip” Taylor founded Monarch Watch in 1992 and Kristen Baum is the organization’s new director – see Monarch Watch: About Us for bios.

Monarch Watch (monarchwatch.org) is an education, conservation and research program based at the University of Kansas within the Kansas Biological Survey & Center for Ecological Research. To arrange an interview with Taylor and/or Baum for further comments, please use the following contact information:

• Kristen Baum, Director, Monarch Watch, kbaum@ku.edu
• Orley “Chip” Taylor, Founding Director, Monarch Watch, chip@ku.edu
• Monarch Watch, monarch@ku.edu, +1 785 864 4441

Reporters may use comments from the following Q&A with Taylor and Baum.

Q: Was this news expected?

Taylor: This news is a shock to all who follow monarchs. The depth of this decline is beyond our experience, and the implications for the future of the monarch migration are surely of concern. However, populations have been low in the past. This count does not signal the end of the eastern monarch migration.

Q: Why is the population so small this year?

Taylor: Monarch numbers are at a near all-time low because of drought conditions last fall that extended from Oklahoma deep into central Mexico. Droughts reduce flowering and therefore nectar production, and monarchs need the sugars in nectar to fuel the migration and to develop the fat reserves that get them through the winter.

Q: Will monarchs recover?

Taylor: Catastrophic mortality due to extreme weather events is part of their history. The numbers have been low many times in the past and have recovered, and they will again. Monarchs are resilient.

Q: What can people do to help monarchs recover?

Baum: To recover, monarchs will need an abundance of milkweeds and nectar sources. We need to get more milkweed and nectar plants in the ground, and we all need to contribute to this effort.

More information about the low population numbers can be found on the Monarch Watch Blog (https://monarchwatch.org/blog).