International Union for the Conservation of Nature | Questions & Answers: What You Need to Know


The International Union for the Conservation of Nature (IUCN) announced it has added migratory monarchs to their “Red List” as endangered, although this list is not connected to the USFWS Endangered Species Act. Therefore, monarchs have not been listed as endangered under the ESA. The IUCN announcement will be great for continuing awareness about the great need for monarch conservation – but it does not have the same ramifications as an ESA listing in the U.S.  

While it’s not the same as being listed as “endangered” by the EPA, it is a positive and important step in the conservation of Monarchs – if for no other reason than it has us all talking about them.  It can also help encourage increasing national efforts to help protect and preserve these iconic butterflies through programs such as Butterfly Pavilion’s Colorado Butterfly Monitoring Network community science program 

What does an IUCN red list assessment mean? 

  • The IUCN scientific team performed a species assessment on the monarch butterfly’s (Danaus plexippus) population status. Monarch population declines have been strong and well-documented in the past decades, so IUCN listing analyzes and stems from the multi-year body of research reporting these declines. The ESA released a similar assessment for their 2020 review on monarchs. 
  • The IUCN designation does not provide any protections or regulatory authority as the ESA ruling would provide and has no impact on the ESA listing process. The designation does inform ongoing global conservation efforts and independent research programs.  

Is the monarch butterfly listed under the Endangered Species Act? Why or why not?  

  • The monarch butterfly IS NOT listed under the Endangered Species Act 
  • On December 15, 2020, the US Fish and Wildlife Service (USFWS) announced that listing the monarch butterfly under the Endangered Species Act is warranted but precluded. This means assessments found the species is at risk and a candidate for listing under the ESA, but other more urgent priorities were selected for listing. You can learn more about this decision on our partner’s website here. 
  • Listing for the monarch under the ESA will be reassessed in 2024 by the USFWS 

I thought monarchs were doing better. What’s going on? 

  • 2021 was a surprising year for monarch butterflies. You may remember recent media coverage reporting increases in counts across North America, including in our own Colorado backyard.  
  • Butterfly Pavilion’s 9th Annual Colorado Butterfly Monitoring Network (CBMN) Report on the state of Colorado native butterfly populations for 2021, revealed heightened sightings and reporting of Monarch Butterflies throughout Colorado. CBMN, celebrating its 10th year of consecutive monitoring in 2022, is a long-term community science project relying on volunteer monitors to record and identify butterflies throughout Colorado.  The report suggests that 2021 was the best year in the past decade for monarch butterflies in the state, which is consistent with the increased monarch sightings across North America this past year.  
  • Butterfly Pavilion was enthused to find that monarchs in Colorado showed an approximate 180% increase from the mean over the past seven years of our monitoring efforts. The results are promising with the 2021 CBMN field season seeing a return of butterfly, monitor, and survey numbers higher than those in 2019, yet there is still more work to do. 
  • Invertebrate populations are well known for large annual fluctuations in size. Fluctuations as the ones we saw with monarchs from 2020-2021 are significantly large and unusual in scale, and the factors responsible for these large changes are not clear yet. This means we are still in the process of understanding monarch population dynamics, and we have much more to learn!  
  • We will likely still see more unexpected changes in monarch populations in the coming years, and changes to our understanding of their dynamics. Until we do, protection of the species and their ecologically and culturally significant migration is still important. Monarchs are often representative of pollinators and invertebrates at large, so monarch conservation programs often support pollinator health at large. 
  • The ecological migration of the monarchs is more at-risk than the species itself, so migratory populations are of particular concern. 

Is this good news? Bad news?  

The IUCN is an impactful international organization that has the power of increasing awareness and conservation participation that can make a direct impact in pollinator health, so this can be seen as an important and urgent call to action. You may use this designation positively to start conversations in the forums you have access to (guests, friends, family, etc.) to create a safer space for our impressive invertebrates. Do note this new designation does not change any existing programs, regulations, or laws around monarch or pollinator health.  With more focus on monarchs there will hopefully be more conservation efforts continued and created to help protect current and future populations.  

What does the future for monarchs look like?  

Monarchs are a resilient and adaptable species! Numbers have been low in the past and may be low again in the future. Fluctuations in population size for invertebrates often mean trials with new survival strategies, which are particularly important in a modern world full of challenges including climatic changes and habitat loss. Monarchs have developed one of the most incredible adaptive strategies in the animal kingdom and perform one of the most spectacular migrations that life has to offer. The Western monarch counts reported an abysmally low number of 2,000 overwintering individuals in 2020. It jumped to 200,000 in 2021. Awareness and action could turn them into 2,000,000! Conservation is in our hands 🦋