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

90%

Long-term decline

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] Recent counts reflect the decline: 9,119 in the 2024 western count and 1.79 hectares of eastern overwintering area in Mexico.[6][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]

Monarch Migration Routes

Eastern Route Western Route Overwintering Site

Reproduction

Breeding Behaviors

Egg

3-4 days

Monarch caterpillar with yellow and black stripes

Larva

9-14 days

Chrysalis

9-15 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 (3-4 days), larva (9-14 days), chrysalis (9-15 days), then adult.[2]

Breeding adults spend 2 to 5 weeks mating and nectaring, and the eastern population typically produces 3 to 5 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 recovery plan addresses the primary pressure points identified by federal and scientific sources: breeding habitat loss, overwintering site degradation, pesticide exposure, and preventable disease risk.[5][18] Each action is designed to scale - through agencies, landowners, and local partners - without requiring centralized coordination that slows implementation.

Habitat Restoration & Protection

Habitat restoration is the foundational intervention. Through USDA NRCS Farm Bill programs, targeted milkweed plantings on agricultural lands, and restoration of tallgrass prairie remnants, the plan rebuilds breeding corridors across the central flyway using regionally appropriate native species.[19][3][9]

Overwintering Site Protection

Oyamel fir forests in central Mexico and coastal California eucalyptus groves are the two critical chokepoints in the monarch's annual cycle - because monarchs require cool temperatures, high humidity, and filtered sunlight to survive winter in dense clusters. The plan supports anti-logging enforcement, canopy restoration, and microclimate management at both sites.[8][6]

Pesticide Reduction

Herbicides eliminate milkweed directly and reduce the fitness of larvae that feed on treated plants. The plan expands integrated pest management, low-input cropping systems, and buffer zones around milkweed patches and migration corridors to reduce both herbicide and insecticide pressure.[16]

Urban & Community Engagement

The Mayors' Monarch Pledge had enrolled over 350 mayors and local government leaders by 2025, committing municipal land to pollinator-friendly management.[17] Urban plantings function as stepping-stone habitat that connects larger restoration areas, and they keep recovery work visible and locally maintained across the migration corridor.[3]

Disease Management

The plan does not pursue captive breeding. Conservation experts have cautioned that captive programs amplify OE infection rates and introduce genetic risks that undermine wild population fitness. Instead, the plan reduces OE pressure through habitat quality improvements, lower overwintering crowding, and public guidance on handling practices that spread the parasite.[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, begin regional milkweed seed collection, prioritize 500,000 acres for restoration, and launch baseline monitoring.

Years 2-3 | 2027-2028

Start large-scale planting on the first 500,000 acres, expand overwintering monitoring, add city-level community programs, and begin formal overwintering protection work.

Years 3-5 | 2028-2030

Expand to 2 million cumulative acres, evaluate egg-laying and larval outcomes, and adapt plantings while scaling pesticide reduction in priority areas.

Years 5-10 | 2030-2035

Scale toward 6 million acres, pursue interim targets (30,000 west and 4+ eastern overwintering hectares), and continue adaptive management from monitoring data.

A 10-year timeline is the minimum for meaningful ecological response at continental scale. Milkweed requires time to establish, monarch populations take multiple seasons to reflect habitat gain, and monitoring needs several years of data to distinguish trend from noise. The phased structure ensures accountability is built into each stage, not deferred 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