An Endangered Species Recovery Plan

SAVING THE
MONARCH
BUTTERFLY

By Jiulin Song

Introduction

What Is Biodiversity?

Monarch butterfly on purple coneflower in Michigan

Tallgrass prairie wildflowers at Glacial Ridge National Wildlife Refuge

Biodiversity is the variety of life across species, genes, and ecosystems.[1] It supports food, water, medicine, and key ecosystem services such as pollination, water purification, and climate regulation.[1]

It also preserves future options: many medical and agricultural breakthroughs come from natural systems. Protecting biodiversity keeps ecosystems more resilient and lowers the risk of food-web disruption.[1]

Species Profile

About the Monarch

Danaus plexippus

Male monarch butterfly with wings spread

233,394

Western count (2024-25)

96%

Drop in 2024-25 count

95%+

Western decline since the 1980s

The monarch butterfly (Danaus plexippus) is one of North America's most familiar insects. Native to the Americas, it is also established in a few other suitable regions.[2] Larvae depend on milkweed (Asclepias spp.), while adults rely on diverse nectar plants.[3]

The migratory monarch was listed as endangered by IUCN on July 21, 2022.[4] On December 12, 2024, the U.S. Fish and Wildlife Service proposed ESA threatened status.[5] The 2024 western count recorded just 9,119 butterflies, a 96% drop from the previous year.[6] The eastern population occupied 1.79 hectares in Mexico during the 2024-25 winter, a partial recovery from 0.9 hectares the year before but still well below the decade average of 2.81 hectares.[7]

Range & Environment

Geographic Range & Habitat

Monarch butterflies in flight during migration in Mexico

Monarchs in flight during their annual migration through MexicoWikimedia Commons

North American monarchs are split into eastern and western populations by the Rocky Mountains.[8] The eastern population breeds across the Midwest and East, then migrates up to 3,000 miles to oyamel fir forests in central Mexico.[8] The western population breeds west of the Rockies and overwinters in coastal California and northern Baja groves.[6]

Monarchs can travel 50 to 100 miles per day, and migration can take up to two months.[8] Breeding habitat includes fields, prairie remnants, roadsides, and urban areas. The key requirement is the presence of milkweed and nectar plants.[3]

World map showing global distribution of monarch butterflies, including native range in the Americas and established populations in Australia, Europe, and Pacific islands

Global distribution of the monarch butterfly (Danaus plexippus)[21]Harald Süpfle / Wikimedia Commons, CC BY-SA 3.0

Monarch Migration Routes

Eastern Route Western Route Overwintering Site

Reproduction

Breeding Behaviors

Egg

3-5 days

Monarch caterpillar with yellow and black stripes

Larva

10-14 days

Chrysalis

10-14 days

Adult

2-5 weeks*

*Breeding adults live 2-5 weeks; the migratory “super generation” lives 6-9 months

Breeding begins in spring when monarchs return north. Females lay single eggs on milkweed leaves.[3] The life cycle is egg (3-5 days), larva (10-14 days), chrysalis (10-14 days), then adult.[2]

Breeding adults spend 2 to 5 weeks mating and nectaring, and the eastern population typically produces 3 to 4 summer generations.[3] Males locate mates by patrolling breeding habitat and pursuing females before mating.[3] The final late-summer generation enters diapause, migrates south, and can live 6 to 9 months.[3] Preferred egg-laying species include swamp milkweed (Asclepias incarnata) and common milkweed (A. syriaca).[9]

Ecological Interactions

Predators, Prey & Competition

Common milkweed stand that supports monarch larvae and nectar resources

Prey

Milkweed plants (larvae), nectar from diverse flowering plants (adults). Monarchs are herbivorous at all life stages.

Black-headed grosbeak, a monarch butterfly predator

Predators

Black-backed orioles, black-headed grosbeaks, spiders, fire ants, paper wasps, and various invertebrates.

Parasites

OE protozoan, tachinid flies, parasitoid wasp Pteromalus cassotis (up to 200 eggs per chrysalis).

Monarchs are herbivorous: larvae eat milkweed and adults feed on nectar.[2] Milkweed cardenolides make caterpillars less palatable, and bright orange-and-black coloration signals that defense.[10]

Monarchs still face major natural enemies. Birds, spiders, ants, and wasps prey on different life stages, and tachinid flies and parasitoid wasps can kill larvae and chrysalises from within.[10][12]

The protozoan parasite Ophryocystis elektroscirrha (OE) is a growing threat. Infection rates in eastern monarchs rose from under 1% in 1968 to about 10%, with impacts on flight performance and survival.[11] Main competitors on milkweed include oleander aphids and other sap-feeding insects, which reduce egg laying and larval performance.[13]

Critical Threats

Why Is the Monarch Endangered?

Herbicide spraying in agricultural habitat where native milkweed is removed

Habitat Loss

Monarch butterflies killed by winter storms at Mexican overwintering site

Climate Change

Large-scale soybean monoculture associated with herbicide-intensive management

Pesticides

Illegal Logging

Monarch decline is driven by interacting threats, led by milkweed loss across agricultural landscapes.[5] Since the late 1990s, herbicide-tolerant crop systems greatly increased broad-spectrum herbicide use, removing milkweed from millions of acres.[14] That change reduced breeding habitat across much of the core migration corridor. Recovery planning estimates roughly 1.8 billion additional milkweed stems are needed.[15]

Climate change compounds the decline by shifting migration conditions and increasing extreme events at overwintering sites.[5] Severe winter storms and forest degradation in Mexico reduce the canopy protection clustered monarchs need.[4] On the California coast, development and land-use change have reduced western overwintering groves.[6]

Pesticide exposure is another major pressure. Insecticides contaminate nectar and milkweed, while herbicides remove host plants needed for breeding.[16] Together, these stressors have pushed both migratory populations far below recovery thresholds, increasing year-to-year volatility in counts.[6][5][15]

Eastern Overwintering Area (1994–2024)

Source: WWF-CONANP monarch monitoring data[7]

Primary Threats

Based on USFWS listing assessment[5] and IUCN review[4]

Recovery Plan

Goals & Objectives

Our plan has three goals: rebuild breeding habitat at scale, protect overwintering habitat, and reduce pesticide exposure. The habitat target is at least 1.8 billion additional milkweed stems across the breeding range, based on USGS recovery estimates.[15][5] These objectives pair ecological recovery with measurable policy and implementation targets.

Monarch recovery matters beyond one species. Monarchs support pollinator systems, indicate habitat quality, and hold cultural significance across North America.[1][17] They are also scientifically valuable because they help track ecosystem response to habitat restoration.

1.8B

Milkweed stems needed across range

6+ ha

Eastern overwintering area target

30K+

Near-term western milestone

Habitat Restoration Targets

Action Plan

Solutions

Native prairie restoration with diverse wildflowers and grasses

Restored native prairie with milkweed and nectar plants that support monarch recoveryWikimedia Commons

The plan targets four pressure points: habitat loss, overwintering degradation, pesticides, and disease.[5][18] Each action scales through existing agency, landowner, and community partners.

Habitat Restoration & Protection

The foundation. USDA NRCS Farm Bill programs fund milkweed plantings on farmland and prairie restoration, rebuilding breeding corridors across the central flyway with native species.[19][3][9]

Overwintering Site Protection

Mexican oyamel firs and California eucalyptus groves are the annual chokepoints. The plan backs anti-logging enforcement, canopy restoration, and microclimate management at both.[8][6]

Pesticide Reduction

Herbicides kill milkweed; insecticides harm larvae. The plan expands integrated pest management and buffer zones around milkweed patches and migration corridors.[16]

Urban & Community Engagement

Over 350 mayors have signed the Mayors' Monarch Pledge, committing municipal land to pollinator-friendly management.[17] Urban plantings act as stepping-stone habitat between larger restoration areas.[3]

Disease Management

No captive breeding: it amplifies OE and introduces genetic risk. Instead, the plan reduces OE through better habitat, less overwintering crowding, and public guidance on safe handling.[18][11]

Native prairie restoration with diverse flowering plants

Monarch butterflies in flight at overwintering region

Cover crops supporting soil health and reducing herbicide reliance

Community pollinator garden at Meadowood with native flowering plants

Restored native prairie with diverse flowering plants and grasses.Wikimedia Commons

Implementation Schedule

Timeline

Year 1 | 2026

Form core partnerships with USDA NRCS and state agencies, begin regional milkweed seed collection, and prioritize the first 500,000 acres for restoration while launching baseline population monitoring.

Years 2-3 | 2027-2028

Begin large-scale planting on the first 500,000 acres, expand overwintering monitoring at Mexican and California sites, and launch city-level community programs alongside formal overwintering protection work.

Years 3-5 | 2028-2030

Expand to 2 million cumulative acres, evaluate egg-laying and larval outcomes at restored sites, and adapt plantings while scaling pesticide reduction across priority regions.

Years 5-10 | 2030-2035

Scale toward 6 million total acres, pursue interim recovery targets (30,000 western monarchs and 4+ eastern overwintering hectares), and continue adaptive management driven by monitoring data.

10 years is the minimum for continental-scale recovery. Milkweed takes seasons to establish, monarch populations lag habitat gains, and monitoring needs multi-year data to separate signal from noise. The phased structure builds accountability into each stage rather than deferring it to the end.[15]

Budget & Resources

Funding

We model a planning-scale 10-year budget of about $200 million. This is an implementation estimate, not a formal federal budget line. For context, NFWF's Monarch Butterfly and Pollinators Conservation Fund has leveraged $82.3 million in impact since 2015 ($31.7 million in grants and $50.6 million in matching funds).[20] Funding sources include NFWF grants, USDA NRCS Farm Bill programs, state wildlife support, U.S. Fish & Wildlife Service contributions, private foundations, and public donations.[19][20]

Volunteers planting native species at a habitat restoration site

Restoration planting at a dam removal site with 4,000+ plants of 24 native speciesUSFWS

Resource	Annual Cost	10-Year Total
Ecologists, field biologists & program staff	$2,000,000	$20,000,000
Native milkweed seed & seedling production	$5,000,000	$50,000,000
Land restoration equipment & supplies	$3,000,000	$30,000,000
Monitoring technology (GPS, weather stations, survey equipment)	$1,000,000	$10,000,000
Education, outreach & community engagement	$500,000	$5,000,000
Partnership coordination & administration	$500,000	$5,000,000
Vehicles & transportation	$1,000,000	$10,000,000
Land leases & conservation easements	$5,000,000	$50,000,000
Research, data analysis & adaptive management	$2,000,000	$20,000,000
Total	$20,000,000	$200,000,000

Budget Allocation

Milkweed & Seedlings 25%

Land Leases & Easements 25%

Restoration Equipment 15%

Staff & Research 20%

Operations, Education & Monitoring 15%

Evaluation

Measuring Success

Monarch butterfly observed through binoculars during a field survey

Field observation during overwintering surveys, used to track yearly population change and test restoration impact.Wikimedia Commons

Success is defined by measurable change in population and habitat outcomes, not by effort or spending. Three core indicators (overwintering counts, habitat establishment, and disease pressure) are tracked annually against fixed benchmarks, making year-over-year progress legible and course correction fast when needed.

Population Monitoring

Our main benchmark is annual overwintering counts. In the east, we track occupied area in Mexico and target growth from 1.79 hectares to at least 6 hectares within 10 years. In the west, we use the Western Monarch Count and target recovery above 30,000.[6][7]

Habitat Metrics

Field teams survey milkweed establishment, nectar cover, and monarch egg and larval density at restored sites each spring and summer. The benchmark is not acres planted but confirmed breeding activity, verified against USGS stem-to-population modeling.[15]

Health Indicators

We monitor Ophryocystis elektroscirrha (OE) infection rates at breeding and overwintering sites. Success means keeping infection pressure stable or lower while survival and migration performance improve.[11][3]

Reporting & Data Collection

We review results annually against the same core measures: eastern area, western counts, habitat establishment, and breeding activity. That keeps reporting transparent and supports fast course correction when needed.[7]

30,000+

Western population target