Monarch Watch Blog

Monarch Population Status

2 August 2011 | Author: Chip Taylor

Monarch Watch turns 20! We started our monarch tagging program in September of 1992 – it doesn’t seem that long ago but I guess that we have been so busy that we lost track of the passing years. We began by recruiting our first taggers through notices in newspapers that called for volunteers and sending out tagging kits as fast as we could put them together. The response by the public was overwhelming and the positive feedback from the participants led to the creation of Monarch Watch, an organization we didn’t envision at the outset.

We started tagging in a down year for monarchs but we didn’t realize it then. Only later did we recognize that the dust veil created by the eruption of Mount Pinatubo had led to a significant reduction in summer temperatures and monarch numbers as well. A lot has happened since 1992. We’ve seen the overwintering population in Mexico increase each year from 1994 to 1996, only to crash inexplicably in 1997. We have seen ups and downs in overwintering numbers – but mostly downs since 2003. In fact, the population has been below the long-term average over the last seven years. Ominously, the four lowest populations recorded to date occurred in the last 11 years. The downward trend is now statistically significant (Brower, et al. 2011) and it is clear that we have entered a new era of monarch numbers.

The great migrations of the 90s are a thing of the past. In the future, we can expect overwintering populations in Mexico of 2-6 hectares. The main reason for the decline is loss of habitat. Monarch habitat has been reduced by at least 140 million acres in the last 10 years – about a fifth of the total breeding area available to monarchs has been lost. At least 100 million acres of habitat has been lost due to the adoption of herbicide resistant corn and soybeans. The herbicide tolerant (HT) crops allow growers to spray their crops with herbicides without affecting the crops. The result has been the near elimination of milkweeds in these row crops and a reduction in monarch numbers – monarch production in these fields was higher when measured in 2000 than in roadsides, old fields, conservation reserve lands and other habitats (Oberhauser, et al PNAS 2001). The adoption of HT crops began slowly in 1996 but has been increasing rapidly since 2003. By 2010 80.7% of the corn and soybeans planted in the United States (161 million acres) were herbicide tolerant. Since these crops are used in rotation, it is likely that milkweeds have been eliminated in more than 81% of the total acreage.

So, where does this leave us and what does this mean for tagging? It means that we will have another year like the last seven and a year not unlike 1992 when we started the program. Specifically, we can expect a low year, perhaps not as low as 2009 (1.92 hectares) or 2004 (2.19 hectares) but close to these numbers. The migration should be particularly low in the New England area and the numbers at Cape May will be low as well. The central region (Ontario, MI, OH, IN, IL) will see a modest migration and could produce more monarchs than the area defined by the eastern Dakotas, MN, WI, and IA. Even though the population will be down from historical highs, there will still be plenty of monarchs to tag. And, as always, you and your fellow taggers will not only have fun but you will also contribute to our knowledge of the monarch migration.

Filed under Monarch Population Status | 3 Comments »

Monarch Tagging Kits for 2011

31 July 2011 | Author: Jim Lovett

Monarch Watch Tag

Our tags for the 2011 Monarch Watch Tagging Kits arrived recently and we sent out the first batch of kits on Friday. Those of you that ordered between January 1st and June 30th of this year should receive your tags within the next few days.

If you haven’t ordered your tagging kits yet, there is still plenty of time before the migration begins – but the tags are going fast. If you would like to participate in monarch tagging this fall, please place your order for tags as soon as possible so that you don’t miss out.

Monarch Watch Tagging Kits are only shipped to areas east of the Rocky Mountains.

As usual, each tagging kit includes a set of specially manufactured monarch butterfly tags (you specify quantity), a datasheet, tagging instructions, and additional monarch / migration information. Tagging Kits for the 2011 season start at only $15 and include your choice of 25, 50, 100, 200, 300, or 500 tags.

Monarch Watch Tagging Kits and other materials (don’t forget to pick up a butterfly net!) are available via the Monarch Watch Shop online at


Filed under Monarch Tagging | 1 Comment »

NYTimes: In Midwest, Flutters May Be Far Fewer

12 July 2011 | Author: Jim

Today’s printed New York Times features “In Midwest, Flutters May Be Far Fewer” – an article by Andrew Pollack about monarch habitat loss and population decline. Monarch Watch Director Chip Taylor is quoted, along with other monarch researchers.

Many Monarch Watchers found this article online yesterday and commented about the featured photo – one of a Gulf Fritillary rather than a monarch. The photo has since been replaced with that of a monarch butterfly and the entire article is available online. Please take a moment to read it and then pass it on! In Midwest, Flutters May Be Far Fewer

Filed under Monarch Conservation | 5 Comments »

Another Honeybee Swarm (video)

6 June 2011 | Author: Jim Lovett

Another swarm of several thousand honeybees settled in a bait hive outside of Monarch Watch HQ on June 6, 2011…

honeybee swarm

Filed under General | 2 Comments »

Monarch Population Status

26 April 2011 | Author: Chip Taylor

Monarch EggsI’ve been monitoring the reports of returning monarchs quite closely this spring. The pattern of the return this year is similar to that seen in 2006 but more exaggerated, with more monarchs moving into the mid latitudes (35-42N) than in any previous April (see Journey North’s first sighting reports). As I pointed out last spring on our email discussion list and in a text written for our May 2006 email update, such early arrivals at more northerly latitudes are not necessarily a good thing. If these butterflies arrive when the milkweeds are above ground and abundant followed by temperatures that allow for normal development of eggs, larvae and pupae – all is well. But, all isn’t well this year. Monarchs arrived in our area (38.97N) in good numbers on the 10th of April with egg laying noted from the 10th through the 15th with some additional eggs on the 18th and later. Milkweeds were scarce -being found in gardens, burned over areas and the edges of roads. Milkweed sprouts in fields were not up or were hidden beneath grasses and weeds. Unfortunately, the temperatures have been colder than normal and none of the hundreds of milkweed stems I’ve surveyed have shown signs of larval feeding even though most of these plants had eggs at one time. At this writing – 26 April – it appears that most of this early reproduction won’t be successful. If so, moving into the mid latitudes earlier than normal will not contribute substantially to population growth this year. In short, it would have been better had these monarchs laid these eggs further south where temperatures were more favorable for growth and development.

In addition to watching the pattern of the returning butterflies, I monitor other conditions – temperature, rainfall, drought, abundance of fire ants, etc., as they play out each month of the breeding season. As you’ve heard from me before, Texas is key. For the monarchs to have a good year, the conditions in Texas for the first generation have to be favorable. If they are, the population grows, as it did last year. If unfavorable, as they have been in a number of years such as 2004, the population declines. Conditions in Texas this spring have been hot and dry – a significant drought. Milkweeds have been abundant and nectar seems to have been available in most locations but due to high winds and temperatures monarchs just kept moving. The result is that monarchs are not off to a good start and the prospects that the population will rebound in the summer months are getting slimmer each day.

At the end of March, I was saying that the population this coming winter would be no greater than 5 hectares due to conditions in Texas. In contrast, at the end of March in 2010 it was quite clear that the population was going to increase and the only question was by how much; it more than doubled from 1.92 to 4.02. It now appears that the 5-hectare prediction was too optimistic. Four hectares (4.02 last year) is possible but not too likely. If the long-range forecasts for the northern breeding areas are accurate, and they have been recently, the prospect for producing a large monarch population in and north of the corn belt is not great. In fact, the population could drop back to 2009 numbers (1.92 hectares), if the summer is as cold as forecast.

In a week or more – weather permitting – first generation monarchs from Texas should begin migrating through this area to colonize the northern breeding areas. The numbers reaching these northern habitats is largely a function of reproduction in Texas and the weather conditions in May. Reproduction is Texas has yet to play out in numbers, but if past seasons are a good measure, the number moving northward should be less than expected based on the size of the overwintering population. Below normal temperatures are projected for May, which, if true, would limit the number of monarchs reaching the milkweed patches throughout the northern breeding area and ultimately the size of the fall migratory population. While we can hope that the long-range forecasts are wrong, and that reproduction will be higher than I’m envisioning, the prospects – at this date – favor a migration that will result in an overwintering population of 2-4 hectares.

We can’t do anything about the physical conditions that drive the monarch population but we can provide the milkweed and nectar resources they need – PLANT MILKWEED!

Filed under Monarch Population Status | 5 Comments »

Monarch Watch Tag Recovery Database Updated

22 April 2011 | Author: Jim Lovett

Nearly 4, 000 records have been added to the Monarch Watch Tag Recovery database, bringing the total number of records to more than 15, 000 for the 1992-2010 monarch tagging seasons.

monarch watch tags

Approximately 2500 records represent monarchs observed/recovered in the U.S. or Canada and more than 12, 500 records represent monarchs recovered at the overwintering sites in Mexico.

Anyone may search the database via

Please note that this is very much a work in progress – we working on acquiring the funding necessary to “scrub” the data (clean up any errors) and create more robust applications for searching and data visualization. Also, you will likely notice records with missing data – this is often due to taggers not returning their datasheets at the end of the tagging season. We are in the process of tracking down the missing data and will update the database as we recover the information.

If you would like to help fund this project, please see our Donation page for details about ways to give.

Filed under Monarch Tagging | 3 Comments »

Capturing a Honeybee Swarm (video)

13 April 2011 | Author: Jim Lovett

A swarm of several thousand honeybees settled in a tree outside of Monarch Watch HQ on April 11, 2011 – they’re not our bees (at least not the bees we have in our building) so we’re not sure where they came from 🙂

honeybee swarm

Filed under General | 9 Comments »

Travelog: Monarchs in Mexico

6 April 2011 | Author: Jim

As you can imagine, seeing the monarchs overwintering in Mexico really leaves an impression on those lucky enough to make the trip. We receive lots of enthusiastic communications about such trips and here is Don and Mary Bernd’s account of of their recent adventure…

monarch on guide's hat

We had visited El Rosario several years ago in the dead of winter when none of the Monarchs were moving around. It wasn’t all that much fun seeing them clustered in the trees all trying to save as much energy as they could in the cold temperature.

Since then we read the book “Four Wings and a Prayer” which suggests good times to view the monarchs flitting around getting ready for the long trip back north. We decided to try again this year and had a very different experience.

Just getting to Angangueo, Michoacán was a trick for us since we winter in Oaxaca, Mexico like the Monarchs. We inquired about routes through Mexico City and were discouraged until we learned about a newer freeway that skirts Mexico City to the north. We used this route to reach Michoacán and made the whole trip easily in one day from our home in Oaxaca.

We stayed at Plaza Don Gabino where we were made to feel at home by the owner and staff. The food was delightful and the atmosphere very welcoming.

We went first to the Sierra Chincua Sanctuary and when we learned that the hiking trail was 6 kilometers long, we opted for horses. Thankfully the guides and leaders were considerate of our years and took it easy on the trail. Neither of us fell off, but we were glad to get off once we reached the wintering areas.

We hiked to the places where the Monarchs were clustered in the trees and there was an eerie quietness. Nobody spoke – we just watched as the monarchs would leave the congregation and take flight. We could actually hear them flitting around as they were the only thing moving in that quiet sanctuary.

As we walked into a clearing where the sun poured down through the forest and a spring of water rose to the surface, the area erupted with thousands of Monarchs tanking-up after a long winter’s nap. Every blooming flower had a garland of wings covering it with busy Monarch flitting here or there for more nourishment.

After spending some time in this sanctuary we mounted our steeds once more for the journey back to our car and it was with physical relief that we dismounted and planted our feet on solid ground once more. The horses made it possible for us to view this wonder and we were glad for the experience, but we were also glad it was over and we could put the ride behind us.

The next day we headed the other direction to El Rosario where the clustering monarchs are a bit closer to the end of the road. We climbed the seemingly endless stairways, resting from time to time and were treated to the sight of monarchs flying from flower to flower all along the way. There were so many that they became commonplace before long. We allowed our eyes to feast on the beauty, majesty, and quantity of monarchs on the wing there at El Rosairo.

We returned to our hotel tired, but happy and satisfied. We had finally seen the monarchs in profusion as we had read about – a dream of 20 years had finally been fulfilled.

Upon returning to our home in Oaxaca I discovered that my wallet had been lost somewhere on our trip. Bummer! The horse trail was inches thick in black dust and a black wallet would be lost forever in that area. We contacted the hotel and they had actually recovered the wallet and were willing to send it to us at our home in Oaxaca. It took only a few days until I was in possession of my identity documents once again and this closed the chapter of our personal monarch watch.

Our pictures don’t do the monarchs justice, but our memory will forever be etched with the sight of thousands of monarchs flitting from one blossom to another, making ready for their return flight to breeding grounds in the United States and Canada.

monarchs on flowers

Filed under Mexico | 2 Comments »

Monarch Caterpillar Dorsal Aorta (video)

29 March 2011 | Author: Chip Taylor

serendipity [ser-uhn-dip-i-tee] -noun.
1. an aptitude for making unexpected and fortunate discoveries

Occasionally, there is a little serendipity in the lab. One Friday, a few weeks ago, I noticed an unusual larva, a fourth instar of a “black” larval mutation we are studying. This particular larva was lighter than most and we could see the blood coursing through the dorsal aorta. I said “Let’s get a camera, this is neat!”

In the course of doing the filming, and not doing it well, I kept getting advice from one of our critter crew members Alicia Bigelow, and I soon realized (another bit of serendipity) that Alicia needed to be in charge of the production of video projects that I’ve always wanted to post to Monarch Watch’s YouTube channel. So, here is the first production: the Monarch Caterpillar Dorsal Aorta. In the voice-over I describe the general pattern of blood circulation in insects and arthropods. Chip Taylor | Director, Monarch Watch

Filed under Monarch Biology | 13 Comments »

Book Review: “Fly, Fly Butterfly”

24 January 2011 | Author: Chip Taylor

Fly,   Fly Butterfly book cover

“Fly, Fly Butterfly” by Diego H. Pedreros Velásquez

Interest in monarch butterflies has grown over the last 15 years. Websites featuring monarchs are now common. Monarchs are the subject of numerous blog postings and periodically the topic of newspaper and magazine articles as well. This interest has also produced an abundance of books about monarchs directed toward parents who might buy them for their children. The quality of these books varies greatly. Some have great artwork and not much of a story, others have a good premise but poor execution and still others are filled with errors – the most common of which is to refer to a chrysalis as a cocoon.

The intent of authors is usually to tell the story of the monarch to inspire a sense of wonder; rarely do authors connect the story to larger issues such as our stewardship of the planet. Most of these stories don’t touch me. I’m jaded, having worked with literally tens of thousands of monarchs and having lent my heavy hand to telling this story myself. So, my emotional reaction to a new book, “Fly, Fly Butterfly” by Diego H. Pedreros Velásquez was a surprise to me.

Mr. Pedreros has written an account of his family’s – and particularly his daughter AmaRa’s – discovery of monarchs and their annual cycle through visits to the Ellwood Main monarch sanctuary in Goleta, California. The family’s increasing awareness of monarchs and the environment that supports them is driven by AmaRa’s curiosity, with the help of an equally curious and devoted father.

The author uses the monarch as a metaphor for how we should face life and connects the fate of monarchs to how humans affect the planet. Excellent photographs by the author of monarchs and wildlife around Goleta are tastefully presented on more than half the book’s pages. The design, layout and artwork in the book capture the sense of wonder and adventure of learning about new things through the eyes of both the child and her father. It’s clear that this book was a labor of love that involved a large and talented team. Perhaps the book’s most unique feature is that it is bilingual, with all the text printed in both English and Spanish, with other languages soon to follow. The writing is clear and direct and it is easy to read and understand the text in both languages. In this age, as we watch our population become increasingly disconnected from the environment that supports them and when it is so hard to get children outside, it is refreshing to have this example of a child connecting spontaneously to the wonders of the natural world.

The book may be purchased with a donation component, whereby 40% of the $20 purchase price may be designated to go to Monarch Watch or another approved organization. For more information on “Fly, Fly Monarch” please visit and

Filed under General | No Comments »