International Monarch Monitoring Blitz

The International Monarch Monitoring Blitz invites community scientists from across North America to come together with the shared goal of helping to protect and conserve the beloved and emblematic monarch butterfly. Data collected by volunteers each year support trinational efforts to better understand the monarch butterfly’s breeding productivity, range, and timing in North America.

This year’s Blitz took place between 29 July and 7 August. You can learn more about the results of this trinational effort, here.

Invitation to participate in the Monarch Blitz 2022

Highlights from the 2022 International Monarch Monitoring Blitz:

For the second year in a row, enthusiastic engagement in the International Monarch Monitoring Blitz surpassed previous participation rates. Here are some highlights from the 2022 trinational effort:

  • 5988 observations
  • 2698 participants from 75 states and provinces
  • 19, 222 monarchs observed
  • 68,847 examined milkweeds

See our full statement, and learn how you can download Blitz Data, here.

A Monarch Blitz map showing the concentration of participation and observations during the 2021 Monarch Blitz.

Click to enlarge

Summary of the last six editions (2017-2022) of the International Monarch Monitoring Blitz, a community science initiative:

  • 7333 participants across Canada, Mexico, and the United States
  • 16,207 observations
  • 281, 637 milkweed plants monitored
  • 99, 605 monarchs observed
  • 38, 753 eggs
  • 33, 221 caterpillars
  • 1956 chrysalises
A graph showing the participation and observation data of the Monarch Blitz between 2017 and 2022.

Click to enlarge

Facts about the Monarch

  • Monarch butterflies weigh less than a gram.
  • There are two recognized migratory routes in North America: Eastern and Western.
  • Migration covers 3,000-5,000 km (2,000 to 3,000 miles) and spans three countries.
  • The Eastern migratory population has declined by more than 80% in 20 years.
  • The Western population has declined by 99% since the 1980s.
  • Everyone can help the monarch butterfly by participating in community science, creating monarch-friendly habitats, and spreading the word about the monarchs’ status and importance as a pollinator.
A monarch butterfly sitting on top of a pink flower.

Click to enlarge

Why Community Science?

The information collected by North American community science observers helps researchers identify priority areas for monarch conservation actions. Thanks to this engaged community of observers, monarch researchers will soon be able to analyze trends in summer breeding population sizes. All partner organizations have agreed to share volunteer-collected data to a central data repository. In this way, anyone can consult and download Blitz data by visiting the TRINATIONAL MONARCH KNOWLEDGE NETWORK.

Two community scientists seated in a field. One writes down observations as another examines a milkweed plant
A community scientist crouching down to look for signs of the monarch butterfly on a milkweed plant

Volunteer participation and the engagement of volunteers grows year after year, and experts believe that the Monarch Blitz database, made up almost exclusively of observations shared by volunteer community scientists, will achieve the original objective set for the Monarch Blitz by the Trinational Monarch Conservation Science Partnership: a rigorous estimation of the size of the summer breeding population, similar to what is done with the overwintering populations in central Mexico and coastal California.

Furthermore, researchers are interested in assessing population trends. Reporting the number of caterpillars and the number of milkweed stems can allow the calculation of a caterpillar-to-milkweed ratio. Researchers can then use this ratio to estimate the size of the population of monarchs that are migrating to Mexico at this time of year.

Which Community Science Program is Right for You?

Participating in the Monarch Blitz requires you to simply track your observations of the monarch butterfly. If you spot a monarch egg, caterpillar, and/or adult or milkweed, no matter where you are near the end of July or beginning of August, you’re encouraged to share your observation with one of several Community Science programs displayed below.

Curious which program is right for you?

Have a look through the programs below to find one that works for you!


Logo Mission Monarch

Mission Monarch


Participating Partner Logo


Western United States

Logo Western Monarch Milkweed Mapper

Western Monarch Milkweed Mapper

North America

Logo - Journey North

Journey North

North America

Logo - Monarch Larva Monitoring Project

Monarch Larva Monitoring Project


The Blitz is organized by the Trinational Monarch Conservation Science Partnership, a collaboration of organizations, including:

Logo Mission Monarch
Logo - Journey North
Logo Monarch Joint Venture
Xerces Society for Invertebrate Conservation
Participating Partner Logo
Environment and Climate Change Canada
Participating Partner Logo - USFWS


Georgina O’Farrill
Head of Unit, Outreach and Partnerships
(514) 350-4336