LINCOLN, Neb. (DTN) -- U.S. Fish and Wildlife Service has until June 6, 2030, to determine if the monarch butterfly should be listed as a threatened species as part of a settlement reached with conservation groups in a federal lawsuit.

At the end of September, the U.S. District Court for the District of Northern California issued a consent decree requiring agency action as the result of a lawsuit filed by the Center for Biological Diversity and the Center for Food Safety in February 2026.

That lawsuit was filed after the USFWS opened a new 60-day comment period that ran through May 19, 2025, on a proposed rule to list the monarch as a threatened species. That was an extension of a comment period that previously ended on March 12, 2025.

Instead of making the listing determination at the end of 2025, USFWS delayed the decision as long-term action but offered no definitive deadline for issuing the rule.

The groups argued in the lawsuit that a continued delay could increase the monarch's chances of extinction.

"On Dec. 12, 2024, over 10 years after receiving the centers' ESA (Endangered Species Act) listing petition, the service proposed to list the monarch butterfly as a threatened species under the ESA," the groups said in the lawsuit.

"Concurrently with the proposed rule, the service proposed designating 4,395 acres of critical habitat in Alameda, Marin, Monterey, San Luis Obispo, Santa Barbara, Santa Cruz and Ventura counties, California. The deadline for issuing a final listing rule and critical habitat designation was due a year from the proposed rule or Dec. 12, 2025. Therefore, the deadline for publishing the final listing rule has passed."

The monarch has been at the center of numerous lawsuits focused on protecting species from agriculture chemicals including glyphosate, Enlist Duo and others.

In 2024, the USFWS said the proposal came about as the monarch's population numbers have been declining. In North America, monarchs are grouped into two long-distance migratory populations including the eastern and western migratory population.

The eastern population is the largest and overwinters in the mountains of central Mexico. The western migratory population primarily overwinters in coastal California.

According to the USFWS, over 4.5 million western monarchs flocked to overwintering grounds in coastal California in the 1980s. In the mid-1990s, an estimated 380 million eastern monarchs made the long-distance journey to overwintering grounds in Mexico, completing one of the longest insect migrations in the world.

The eastern migratory population is estimated to have declined by about 80%, the USFWS said in its 2024 announcement.

The western migratory population has declined by more than 95% since the 1980s, putting the western population at a greater than 99% chance of extinction by 2080, according to the USFWS. During this same period, the probability of extinction for eastern monarchs ranges from 56% to 74%.

The USFWS proposal includes conserving critical habitat for the species at a portion of its overwintering sites in coastal California.

Read more on DTN:

"Lawsuit Seeks Monarch Protections," https://www.dtnpf.com/…

Todd Neeley can be reached at todd.neeley@dtn.com

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