Tag Archives: monarch butterfly

Monarch butterfly populations went down 80% in 21 years

A new study has found that monarch butterfly populations have dwindled at alarming rates in the past couple of decades, dropping on average by 80%. In the forests of Mexico, they went down by as much as 90%.


The monarch butterfly (Danaus plexippus) is known for its annual southward migration from Canada and the US to Mexico, which takes several generation. Usually, the initial populations overwinter in various coastal sites in central and southern California. The overwintered population of those east of the Rockies may reach as far north as Texas and Oklahoma during the spring migration. The second, third and fourth generations return to their northern locations in the United States and Canada in the spring.

However, in recent times, their populations have been going down dramatically – and the main cause, as usually, is us – our pesticide use, to be more precise.

The main food source of these butterflies is milkweed, also an important nectar source for native bees, wasps, and other nectar-seeking insects. The increasing usage of pesticides for agriculture has led to a decline in milkweed habitats.

“A monarch that leaves its wintering grounds in Mexico will never make it to Vermont,” said Mark Ferguson, a biologist with the Vermont Fish and Wildlife Department, in an interview with The Boston Globe. “Instead, several generations are born and die along the way, meaning that the grandchildren or great-grandchildren of the monarchs leaving Mexico eventually arrive in Vermont each summer. Because monarchs need milkweed to reproduce, anything we can do in Vermont to promote this vitally important species will help monarchs thrive.”

Ferguson believes that Vermont will play a key role in the future of monarchs, because its meadows and old fields provide habitat for milkweed. This means that if officials support the re-expansion of milkweed, the butterflies could be saved. Ferguson has recommended that people should limit the use of insecticides and herbicides to the strict necessary.

Bonus Fact: Monarchs are foul-tasting and poisonous due to the presence of a specific type of steroids in their bodies, which the caterpillars ingest as they feed on milkweed.

Why pollinators are important and why we need to act now to protect them

It’s been in all the headlines: monarch butterflies are in decline, honey bees are experiencing colony collapse disorder (CCD), and our future food supply appears to be in peril. The importance of preserving pollinators has even reached the White House, as President Obama issued a presidential memo in June 2014 that directed federal agencies to 1) develop a Pollinator Health Task Force, 2) develop a Pollinator Research Action Plan, and 3) require agencies to implement plans to increase and improve pollinator habitat on federal lands. It is definitely a serious issue!

What are the issues?

Photo credit: USFWS (Adult monarch butterfly by Tina Shaw/USFWS).
Photo credit: USFWS (Adult monarch butterfly by Tina Shaw/USFWS).

Monarch butterflies have been declining significantly, reaching the lowest count ever recorded during the 2013-14 migration (USFWS, n.d.). The migration route between the U.S. and Canada, a 3,000 mile journey, has become more challenging because of habitat loss, particularly the loss of milkweed (the species’ only food source), and mortality caused by the use of pesticides.

Pollinators are in decline. There are many types of pollinators in the environment. In addition to honey bees, wasps, and butterflies, hummingbirds, bats, ants, beetles, and flies also can pollinate plants. These species are typically underappreciated, if not feared, by people, leading to a lack of concern for their conservation. For example, Regan et al. (2015) noted that 2.5 bird and mammal pollinator species are moving up the IUCN Red List by one category toward extinction every year.

Neonicotinoids, one of the most widely-used pesticides are impacting on non-target species. Honey bees are exposed to this pesticide because its residue is found in nectar and pollen. In fact, it persists in the soil and in woody plants for up to six years after it is applied (The Xerces Society, 2014). While there is not yet a direct correlation between colony collapse disorder and neonicotinoids, it is likely that honey bees become more susceptible to parasites and pathogens, the sub-lethal effects mentioned in Goulson (2013).

What’s being done?

EPA recently updated pesticide use labels to include a bee advisory box. The new advisory box includes a bee image to alert users to take additional precautions and observe any specific restrictions for pesticide use to better protect pollinators. EPA is also currently conducting a registration review of these products and working with the USDA to conduct additional scientific research (EPA, 2015).

In the U.S., federal agencies are banning or phasing out neonicotinoids. The first agency to ban entirely them is the U.S. Fish and Wildlife Service for use in national wildlife refuges, starting in 2016. The National Park Service has begun the process of phasing them out for most applications in national parks. Several states are also considering banning these pesticides. In Europe, the European Committee has banned three neonicotinoids for at least two years, and will decide on a total ban by late 2015.

What can you do?

Create pollinator habitat. Plant milkweed! Next time you plan out a planting project, go online and find some native plants that support pollinators, including milkweed, the sole food supply for Monarch butterflies. This site provides guidance for native pollinator plants based on the region of the country, so you can tailor your choices to those most appropriate in your area.

Use best management practices. According to the Xerces Society (2014), household products approved for use in gardens, lawns, and on ornamental trees have manufacturer-recommended application rates up to 120 times higher than those approved for agricultural crops. There are a multitude of resources to identify best management practices you can use to protect pollinators. Here are some links EPA recommends:

Encourage others to protect pollinators. Remember, change takes place when we model the behavior we hope to see in others! Why not hold a pollinator party and raise awareness of this important issue?

The bottom line is that we all need to consider our future without pollinators, or if there even will be a future without them.


  1. Douglas, M.R., Rohr, J.R., and T.F. Tooker (2014). Neonicotinoid insecticide travels through a soil food chain, disrupting biological control of non-target pests and decreasing soya bean yield. Journal of Applied Ecology. DOI: 10.1111/1365-2664.12372
  2. Environmental Protection Agency (2015). Protecting Bees and Other Pollinators from Pesticides. Retrieved from http://www2.epa.gov/pollinator-protection
  3. Goulson, D. (2013). An overview of the environmental risks posed by neonicotinoid insecticides. Journal of Applied Ecology, 50, 977-987.
  4. Hopwood, J. Vaughan, M., Shepherd, M., Biddinger, D., Mader, E., Black, S.H., and Mazzacano, C. 2012. Are neonictinoids killing bees? A review of research into the effects of neonictinoid insecticides on bees, with recommendations for action. The Xerces Society for Invertebrate Conservation. Retrieved from http://www.xerces.org/wp-content/uploads/2012/03/Are-Neonicotinoids-Killing-Bees_Xerces-Society1.pdf
  5. Regan, E.C., Santini, L., Ingwall-King, L., Hoffman, M., Rondinini, C., Symes, A., Taylor, J., and S.H.M. Butchart (2015, 27 March). Global trends in the status of bird and mammal pollinators. Conservation Letters. DOI: 10.1111/conl.12162
  6. The White House, Office of the Press Secretary (2014, 20 June). Presidential Memorandum – Creating a Federal Strategy to Promote the Health of Honey Bees and Other Pollinators. Retrieved from https://www.whitehouse.gov/the-press-office/2014/06/20/presidential-memorandum-creating-federal-strategy-promote-health-honey-b
  7. The Xerces Society (2015). Are neonictinoids killing bees? Retrieved from http://www.xerces.org/neonicotinoids-and-bees/

About the Author

This article was written by Dr. Carol Pollio, Program Director, Environmental Science at American Public University.

Dr. Carol A. Pollio has been the Program Director for the Environmental Science Program for more than 8 years. She is also the Chief of Natural Resources and Science for the National Park Service, National Capital Region. In this position, she manages a staff of technical experts in various natural resources fields, providing scientific advice and assistance to 14 national parks. Dr. Pollio has more than 38 years of experience in the Department of Interior, primarily in field positions, including positions in natural resources management, federal law enforcement, and wildland and structural firefighting.

A 31 year veteran of the US Coast Guard Reserve, CAPT Pollio was activated in support of Operation Enduring Freedom in 2003 and deployed to the Gulf Oil Spill in 2010, serving as Liaison Officer to Santa Rosa County, Florida. As a member of a deployable unit for 7 years, she traveled to Portugal, Turkey, and Panama to conduct foreign port security exercises.

Dr. Carol Pollio received a Ph.D. in Environmental Science and Public Policy from George Mason University, a Master of Science in Environmental Science from Marshall University, and a Bachelor of Science in Natural Resources Management from Rutgers University.

monarch butterfly

Weird cloud picked up on radar was actually Monarch Butterflies

monarch butterfly

The US Weather Service captured this strange anomaly, which was in fact the monarch butterfly “cloud”. Image: U.S. National Weather Service.

Radars picked up a “strange cloud” with a bizarre shape above the US Midwest. Upon a closer look, it was revealed that the cloud was actually monarch butterflies traveling from Canada to Mexico – an iconic migration which has been less and less visible in recent years, but may make a resurgence in 2014.

Monarch butterflies are the most iconic butterfly species in North America. Every year, they migrate from the US and southern Canada to Mexico, in one of the most spectacular displays in the natural world. Apparently, it’s not spectacular only from the ground, but also on radars.

Radar maps from St. Louis, Missouri, showed something unusual last week: a large, slow-moving cloud that was changing shapes as it drifted south. For a meteorological formation, it look very bizarre, and to make things even stranger, it seemed to constantly change its shape. For a while, radar operators were baffled; what could it be? After a while, they realized that it wasn’t in fact a cloud, but it was actually monarch butterflies, migration towards Mexico by the millions.

“Keen observers of our radar data probably noticed some fairly high returns moving south over southern Illinois and central Missouri,” the National Weather Service says. “We think these targets are Monarch butterflies. A Monarch in flight would look oblate to the radar, and flapping wings would account for the changing shape!”

The Monarch Butterfly. Photo: William Warby/Flickr.

Indeed, further reflectivity analysis confirmed that the cloud had a biological nature – and this is much welcomed news! Biologists have reported year after year a significant decrease in their numbers and in August this year, the Center for Biological Diversity and the Center for Food Safety filed a legal petition requesting Endangered Species Act protection for the monarch and its habitat. A definitive response has not been issued.

Still, while it’s too early to draw any positive conclusions, there are indeed some good signs. Experts in Mexico explain that the butterflies have started their migration earlier than usual this year, but it’s still not clear if this means their numbers are starting to rebound.

Their migratory adventure will span over three countries, over 2,500 miles, and on average, lasts 4 butterfly generations. We’d like to wish them good luck, and hope their numbers continue to grow!