Monarch Watch Blog

Where are the monarchs??

Friday, July 18th, 2008 at 2:21 pm by Chip Taylor
Filed under Monarch Population Status | 45 Comments »

“Where are the monarchs?” has been a common question asked of us over the last month or so and the following is the best answer I can provide at this time.

Thanks to all of you who have contacted us with your assessments of the status of the monarch population. The vast majority of reports indicate that the monarch population appears to be much lower than normal. Most of these observations have been from areas where the monarchs are between broods and sightings of adults are usually low in early and mid July. So, this aspect of the reports is not alarming. The general absence (or low numbers) of larvae, as indicated in many reports, is of greater concern. The larvae present now mature into adults in late July and early August. These butterflies produce the offspring (from eggs generally laid from the 20th of July to the 10th of August) that become the butterflies that join the fall migration. Again, with few exceptions, unless you are all missing something out there, the number of reproducing adults over the next three weeks will be low, to be followed by a relatively small migratory generation. This assessment could be wrong of course and let’s hope that this is the case.

Assuming our collective assessments are, in fact, correct and that the population is low, how do we account for the lower than expected number of monarchs?

Here is what I know about the monarch population (December 2007 to the present):

1. The overwintering population in Mexico measured 4.61 hectares, a bit lower than the average of about 6 hectares in recent years, but not alarmingly so.

2. Although mortality during the winter was higher than normal at one location on Cerro Pelon, overwintering mortality appeared to be normal at other locations.

3. Examination of monarchs at several colonies at the end of the season showed them to be in remarkable condition with large numbers of nearly immaculate butterflies with large fat bodies. The proportion of monarchs in poor condition appeared to be lower than normal.

4. The migration into Texas appeared to be quite good, although a bit delayed. Some monarchs lingered at the overwintering sites as late as the first week of April. Various observers in Texas reported large numbers of returning adults and others subsequently reported large numbers of larvae on milkweeds in pastures south of Dallas.

5. March temperatures in Texas were neither too hot nor too cold and the simple temperature based model I’m developing suggested at that time that the overwintering population might be as high as 8 hectares. All appeared to be well in Texas and on track to produce a large number of first generation monarchs that could colonize the northern breeding grounds.

6. The first generation monarchs usually pass through Kansas from the last few days of April through the first week of June. During good years, the movement of first generation monarchs through this area can be quite conspicuous with many of the passing monarchs stopping to lay eggs on the blooming milkweeds. There was no obvious “flow” of first generation monarchs through the area this year and relatively few eggs and larvae were found on milkweeds in May and early June.

7. This observation gives rise to two questions: a) was the first generation much smaller than expected? and b) are there other explanations for the relatively low numbers of monarchs that reached the northern breeding grounds? Or, is the explanation some composite of these two possibilities?

8. At this point there is no way to assess the success of the first generation in Texas and other southern states. If the fire ant population was higher than it has been in recent years, predation by these ants could have had an impact. However, I don’t think the ants are widespread or abundant enough to have a large-scale impact on the population. The weather during March and early April in Texas was favorable for reproduction so I’m inclined to look to another cause.

9. May, the moving month for first generation monarchs, was cold – throughout the entire northern breeding range. It was also a period of frequent storms and heavy rains, particularly during the second half of May. Early June also saw heavy rains, especially in the east north central and central portions of the country.

10. In spite of these limiting conditions, bursts of monarchs reached some northern breeding areas, notably Iowa, parts of Ontario, and southern New England.

11. So, how could the May and early June conditions have limited the monarchs? In a few words, by: a) limiting dispersal, b) reducing egg laying, and c) increasing mortality of adults. All together such effects result in a reduction of the potential fecundity of the generation and the “realized fecundity” is lower than expected. The impact of lower temperatures and heavy rains on survival of larvae are unknown but might also have reduced the population.

12. What about the future? The monarchs could surprise us. If temperatures are moderate for the remainder of the summer and a substantial number of eggs are laid from 20 July to 10 August, the population could rebound.

13. As a number of you have pointed out, this year is not a good year for butterflies in general. This means that the parasites and predators that make a living feeding on a broad range of lepidopterous larvae are starving or not reproducing in good numbers. If parasites and predators are low, the result could be that there will be a reduction in the loss of monarch larvae during the last generation giving rise to a larger migratory population that seems to be indicated at this time.

Based on what we know now, my expectation is that the overwintering population in Mexico will be lower than the 4.61 hectares measured last year. As always, I hope my predictions are overly pessimistic.

  1. 45 Responses to “Where are the monarchs??”

  2. By chris molnar on Jul 19, 2008

    tonight i searched for a web site on the monarch because we have not seen a single one yet this year. we live in the southeastern part of michigan and wanted to know if we were the only ones. we’ve been growing milkweed for a few years and have many butterfly flowers and bushes. monarchs have been laying eggs on the milkweeds for a couple of years and we’ve even had them hatch on a makeshift branch. there has been several other types of butterflies in our yard but no monarchs.

    chris & melissa molnar

  3. By Carole Olson on Jul 23, 2008

    I have worked at the Ludington State Park, Ludington, Michigan for 10 years – this year there are VERY few Monarchs – and VERY few Monarch eggs on the Milkweed!

    Is this due to the flooding, etc. this Spring as the Monarch’s came North from Mexico? I have never seen so few in our area.
    Thank you.
    Carole Olson

  4. By Bobbi on Jul 24, 2008

    I am concerned about the where abouts of the monarchs. I have a hatchery in my house and last year hatched out 84 beautiful monarchs into the world. The first one that came to my yard last year was in late june early july. This year ,(now middley of July), NOTHING. NOT ONE MONARCH. PLEASE HELP.

  5. By Debbie in Northwestern Ont on Jul 26, 2008

    From Waystation 444:
    Still no Monarchs here in Thunder Bay, Northwestern Ontario. Thanks for the information. When I looked through the reported sitings for different areas, I noticed many people mentioned spraying for gypsy moths…I think it was in the Minnesota/Wisconsin sites, but not sure now. Could that have impacted the monarchs? Milkweed plants are thriving this year, since no cats…here’s hoping for their return next year. A local entomologist thought that perhaps the absence of southerly winds this year also had an impact. Could that be so?

  6. By Brian Wolfe on Jul 29, 2008

    I’m in winnipeg manitoba, last year the monarchs arrived in early june. I have 7 milkweeds in my yard and at least 20 adults matured on the plants. this year i have yet to see one monarch.

  7. By J. Imhoff on Jul 31, 2008

    Very interesting review of the issues involved with this summers’ (2008) Monarch counts. Thanks for outlining the issues for us.

    Can you please post a link to the ‘assessments’ to which you refer in your second paragraph? I am interested in why our monarchs seem to be so elusive so far this summer.

    And also a link to the Kansas Phenology Project? Usually when my Tithonias are in bloom they are full of monarchs. Not so thus far this summer, but maybe the Tithonia bloom is early this year. Or the monarchs are later than usual.


  8. By Monarchfan on Aug 1, 2008


    Here in Massachusetts, we have also noticed almost no butterflies this year in contrast to last year, when we thought they were more plentiful than usual. I saw my first monarch yesterday. We have Asclepias and Butterfly Bush in the yard that had frequent visitors last year. Hummingbird moths…none this year either. We have also noticed an unusually low population of mosquitoes. Despite all the rain I have seen no more than a half dozen mosquitoes all summer. We own a Mosquitoe Magnet and never once thought of putting it out. There were five pair of swans on our local pond last year and this year there has only been one swan. A very odd year.

  9. By Debra Barnes on Aug 5, 2008

    Hi, we usually don’t see a lot of monarch here (TN River area, TN) until the last two or three generations of year. Still we are seeing almost nothing. There is one female hanging around at my boyfriends on his milkweed. And I have only had six cats (four of which died from tacnids, after bringing them inside, but two did morph and go free!) Still nothing like we usually see. We enjoy rearing them and hope to see more in the next few weeks. Just for the record we have tags and set out over 500 plants this year. Keep the faith!

    New Johnsonville, TN

  10. By Joanne Peek on Aug 6, 2008

    Here in Egg Harbor Township,NJ I have not seen one this year. This is a change from previous years in which there were eggs and instars by this early time in Aug. In fact, I have seen only one black swallow tail and and one Eastern Yellow Swallow tail. It seems as though the butterfly population is down entirely. As mentioned in a previous report, we have had spraying for gypsy moths this year but not on my property. Hoping to see some Monarchs soon.

  11. By Joanne Peek on Aug 7, 2008

    Eureka!!! One lonely monach was flying around the garden today. She had one ripped wing and seemed tired taking frequent rests on various plants. She did lay several eggs before flying off.

  12. By Frederica Scott on Aug 8, 2008

    Having the identical experience in East Central Ohio as written by C. Mollnar. We have a very large patch of milkweeds, last year I could count 75 caterpillars, have seen one this year and then found it dessicated 2 days later. Also not seeing many Tiger Moth larvae or eggs of, which compete for the milkweed at this same time of the year. Have one monarch butterfly and a few swallowtails.

  13. By Laurie on Aug 8, 2008

    We have not seen any monarchs here near Campbellford, Ontario either. This time last year we were hanging out with the caterpillars. I’ve been out in the rain (because that’s all it’s doing here this summer) looking for larvae, but with no luck…the earwigs seem to be taking over the milkweed…

  14. By Libby deMartelly on Aug 11, 2008

    No monarchs seen here in southwestern NH…. Actually I saw one lone monarch … about a week + ago. She looked very “fresh.” Haven’t seen any larvae. It has rained ALL summer here… ???

  15. By Shelley on Aug 11, 2008

    I live in Grand Prairie, Texas and noticed the whole population of all butterflies not as abundant as previous years. Alot of people were using spray for bag worms last year. (They were freakishly abundant.) Of course my neighbors and I did not spray. Our city also sprayed for the numerous mosquitos that have plagued us for a number of years. Also, alot of land through the Monarch Migration trail has been cleared for developement in my area. Hopefully, we will all see an increase during migration. I am happy to report I have seen a female Monarch on August 8, 2008 🙂

  16. By Andrea on Aug 13, 2008

    I’m from Winslow Twp. N.J. I found an dessicated, tagged, Monarch 2 days after severe thunderstorm activity including hail, heavy rain and winds. I also had several more flying around my vacation home in Cape May, N.J. where I have a small milkweed plant growing.

  17. By Roxana on Aug 13, 2008

    We have seen almost no monarchs this year in the Hudson Valley area of NY. None at all in the butterfly garden. All the butterflies seem to be down, even the cabbage butterflies that used to swarm over our radish flowers. I do have some milkweed tussock moth cats on the milkweed, but that’s about it. I was hoping it was just our immediate area, but looks like it’s everywhere.

  18. By Jo Johnstone on Aug 13, 2008

    We have seen only a few monarchs this season here in southwest Ohio. I do have three caterpillars that were found as eggs in the Lebanon area. There have been a few more eggs found in the last day or two by a friend who will share with me. I sure have missed the usual 100+ that I have raised by now. I didn’t order tags since there are so few butterflies. I am keeping the faith also that next year will be back to normal. It’s great to share my concerns. Hope there will be an answer soon. Chip can do it!!

  19. By Elizabeth Heberer on Aug 13, 2008

    I live in the St. Louis area. The monarchs are really scarce this year. I keep checking my milkweed plants but I have found not one egg. But the swallowtails are swarming. Every day I see a couple or more on my butterfly bushes. I still miss the monarchs. I will keep looking for them.

  20. By Teresa on Aug 15, 2008

    I live in Northeast Ohio, and I was wondering if perhaps the monarchs weren’t laying eggs on our milkweed due to my husband unkowingly putting ant poison by the soil we grow the milkweed.
    But now I think perhaps our weather hasn’t been hot enough for them. I usually get 300-400 butterflies to hatch. This year it is only 60. I haven’t seen many butterflies at all, 3 monarchs and a couple of swallowtails.

  21. By patrickb on Aug 16, 2008

    And I thought I was alone! I have a dedicated butterfly garden in Edmond, OK. Last year raised several Monarch larva indoors due to observed wasp predation outside. This year I’ve seen only a couple of females, no eggs noted. Milkweed has thus far only attracted the aphids.

  22. By Dick Heil on Aug 18, 2008

    One lone male Monarch arrived at our Monarch Waystation (in Western Kansas) on August 12 and he is still here a week later. He is probably “lookin for love” but uless he mates with a hummingbird he is out of luck.

  23. By Jody Koogle on Aug 18, 2008

    I have a small garden, but this the past few weeks I have observed a good many Monarchs and today I found at least 10 caterpillars. Here in west/central MD, I spoteed my first eggs on June 13 and they have been sporadic up until the last 10 days when they really picked up. My swamp milkweed is in full bloom and is really doing the job. The kids love it!

  24. By Georgianna Counterman on Aug 19, 2008

    We have been rearing several larva removed from our milkweed, four hatched last week.
    Another four turned pupa last night. We have taken notice of the shortage to. Has any one noticed that the milk weed feels dry and stressed. I also observed orange clusters of powder, red tiny spiders, alot of aggressive black wasps and leaf hoppers. The mosquito population has made the summer very unjoyable. I’m hoping we all get some relief
    soon – Georgianna Counterman, Kenosha, WI.

  25. By Tracy Leinbaugh on Aug 19, 2008

    This is very depressing. I was hoping the situation in southeastern Ohio was unusual, but it appears not to be. I have seen only three Monarchs this year; all in the past week. We have dozens of milkweeds, but no eggs or caterpillars. Few butterflies this year of any kind, and usually there are many. There has been no spraying for anything here, and little to no development. They just don’t seem to be getting here this year. Last year we had quite a few Monarchs by this time, lots of eggs, and many cats.

  26. By Dottie Carter on Aug 19, 2008

    I am beginning to see more monarchs here in West St. Louis County, MO. I have managed to tag 3 already (my frst season for tagging). I also have several cats & one spun it’s chrysalis today – Yes!! Another looks good to go any day. Am currently “raising” my third batch of black swallowtail cats on the fennel for this summer. Also have seen several tiger swallowtails and painted ladies. Due to all the spring rains my garden is the best it’s ever been……..

  27. By Tracy on Aug 22, 2008

    Yesterday we were at Seaside Park, NJ about a block from the ocean and we counted 3 monarchs within a 5 minute time frame. I’m sure we would have seen more had we been looking.

  28. By sophie on Aug 22, 2008

    we usually see loads of monarchs here in winnipeg every summer. sometimes we also see them at Manigotagan on the East side of L.Winnipeg. this year:nothing! and not just the monarchs, no Lunas, no swallowtails, no painted laddies. a few Mourning cloaks, a couple of cabbage butterflies. that is iT! what a dismal summer with out the flutterings! Hope next year is better! has anyone had a normal dose of butterflies this summer?

  29. By Jude G on Aug 23, 2008

    I am a beekeeper who grows a huge garden of native plants that butterflies and pollinating insects, as well as hummingbirds, ‘flock’ to but this year I am very concerned because I’ve seen only 1 monarch visit my gardens in Rehoboth, MA in the past few weeks. I saw some monarchs while visiting on Prudence Island, RI. And back in late July while visiting the Berkshires, I saw a few monarchs there but overall, the monarch sightings are few and far between–depressing.

  30. By Julie on Aug 25, 2008

    Well now I know it’s not just me! I live in Central Indiana and by this time last year had seen 2 different “waves” of caterpillars on my milkweed. This year I have seen 2 lone caterpillars and probably fewer than 5 adults. Not very many other butterflies either, more swallotails than anything else,and not many of them either.

  31. By Johanna Vienneau on Aug 27, 2008

    I haven’t seen many adult Monarchs, although on August 24 I saw four flying over the Moats (about 2800 feet elevation) in Conway, New Hampshire. But, I have started collecting cats for my classroom (and to tag). Every hay field where I normally collect is full of cats, both small and large. Hay fields are great because the milkweed is young and fresh. I collected 35 big cats in one small patch, about 1/4 of a football field in size. It is hard to collect fresh milkweed to feed them, because I keep finding more cats, including very tiny ones, on the milkweed I cut. If the larvae all successfully turn into adults, there will soon be plenty of butterflies.

  32. By triciamoney on Aug 28, 2008

    Hi everyone,
    Greeetings from Fairfield CT – about 40 mile noeast of NYC on the Long Island sound.
    I am anxious for the arrival if our friends. I haven’t seen any that would be headed south. I did at this time last year. Ihad tagged at least 50 by now. Maybe some of them were actually headed north. So far ai tagged 10 the last of them was 2 weeks ago. They were headed north, i am sure. Eggs were laid and i saved them all from beetle activity and am on the way to giving birth to about 20 butterflies in the next few days. I have to say I am relieved that people up the coast from me haven’t yet reported any sightings. I will get a complex thinking the monarchs won’t be stopping at the MONEY MOnarch Motel in Fairfield CT!

  33. By Mary Rector on Sep 1, 2008

    Greetings from Knoxville, Iowa
    We wanted to let all of those butterfly watchers out there we have seen a tremendous amount of monarchs this summer and have an unbelievable amount of caterpillars. Everywhere we look there are caterpillars. My first graders are bringing in caterpillars and I am raising them in a tank. I look to tag many more butterflies this year than I have in the past ten years! Let’s hope this year is a rebirth year!!!

  34. By elaine friedrick on Sep 2, 2008

    8/31/08 9/01/08 appt 50-100 monarch butterflies roosted in the Paper Birch Trees in our back year…near GB WI

  35. By Mike Sproule on Sep 3, 2008

    I am in Niagara Falls, no sign of any caterpillars on the Labour Day weekend as there was in the past few years, any idea’s, are we just early or?

  36. By Kathy Munger on Sep 4, 2008

    I am so sad about the low number of larvae to be found this year in the Grand Rapids, Michigan area, Rockford, specifically. Each year I tag butterflies with my students at Meadow Ridge Elementary. Our mascot is the Monarch Butterfly. I have only two this year. Seems to be the case most places.

  37. By Elizabeth Heberer on Sep 6, 2008

    I am so happy, I have found some monarchs on my plant, the one is in his chyslis and the other is eating like a pig, so it wont belong. god bless the butterflies

  38. By Kathy Panetta on Sep 6, 2008

    I live in Ledgewood, in northern, NJ., and have also noticed very few butterflies in general this year, (except for the Cabbage Butterfly). Thank goodness the Monarchs that have been here were busy laying eggs in my milkweed garden. I gather them and raise the cats inside due to the predatation in my garden, and was coming in with many eggs each day between the the beginning and middle of August this year, (later then last year). Have tagged and released about 40 so far, but am holding about 25 until tomorrow when tropical storm Hanna clears out. Hope the ones I let go yesterday are O.K. Have about 10 more butterflies that will be emerging tomorrow morning, and some more chrysalis’s that will mature. Had so many cats pupaeting I ran out of room in the habitat I built, and resorted to using some plastic “critter keepers” I got at the pet store and put a screened top on my old aquarium for more. Still needed more room so I found a wire and net, 3 story toy storage unit at the dollar store that is hung, that I converted to a caterpillar condo. Will be releasing close to 150 this season. Am worried that this active hurricane season doesn’t dessimate their migration to Mexico.

  39. By Beth Niblack-Sykes on Sep 24, 2008

    Have had a habitat & been raising Monarch cats for about 10 years now. We had a slow start here in Madison WI but the egg laying picked up so that I had more eggs than I could raise. The eggs I left behind were predated- emptied out so only egg husks remained. I never saw any evidence of any “wild cats” making it on my milkweed. Only the ones reared indoors (about 60 in all)made it to adulthood. What predator robs the eggs? It seemed most significant this year above any of the previous years.

  40. By Barbara Meitner on Sep 28, 2008

    I live West of Panama City beach. about 1/4 of a mile from the beach. We have lived here six years and have alway had Monarchs. This is the first year we have not seen even one anywhere around here. We’ve only seen two honey bees, too. I have a lot of milkweed and flowering plants. Most for butterflies, bees and hummingbirds. We have a lot of hummers this year. I had to put out twelve feed for them. I’ve read that geneticly modified corn creates it’s own pesticide in the pollen and it’s widely broadcast by the wind. Could this be killing the butterflies and bees?

  41. By Suzanne Strider on Oct 16, 2008

    I live in Durham, North Carolina and have noticed very, very few monarchs this season. My last few caterpillars have died (maybe due to the colder temperatures but seems like a lack of interest in eating). I saw exactly one female laying eggs the whole season. If the rest of these hatch and are viable, I will have only raised about 90 butterflies this season and have tagged only 7 in the wild! I saw a wasp eating at least two of the cats and I have many more of those little red bugs on my milkweed this season also. The eggs that were laid were laid very late in the season. In the past 6 or 7 years, all my butterflies would have long since hatched and moved on by this date.

  42. By Yvonne Coil on Jan 31, 2009

    Tell Beth Niblack-Sykes that if she has any
    Praying Mantis.
    That is the culpert who is eating the eggs of Monarch.
    I have to keep my Monarch eggs gathered because of the Praying Mantis.
    I’ve released 80 some each year for the past 4 years.I have probably 75 to 80 milkweed in my flower garden.
    I’m looking for different kinds of milkweed seed.
    I’ve ordered several butterfly bushes and the Monarchs really love them.

  43. By Cindy Masiejczyk on Feb 28, 2009

    Last week I counter over 20 Praying Mantis Egg cases in a meadow that was planted in the Pennypack Park, part of Farimount Park in Philadelphia, Pa. Is anyone doing serious reseach in the growth of the large Chinese Praying Mantis and their impact on Monarchs, bumble bees, tree frogs, humming birds, spiders. I just read that the Mantis eats all of them, but I don’t know if the articles I read from the Google Internet meant the Chinese Mantis. On a visit to Cape May several years ago, I did see a Mantis with a Monarch meal, and several other Monarch wings on the sand below. Every summer I have come across several of the large mantis in the meadows of the park. This year I did not see even one Garden Spider, the large yellow ones in the meadow, and only a few Monarchs among the Meadow plants.

  44. By delphine on Sep 24, 2009

    I was walking my daughters dog in downtown Saranac Lake, NY when I spotted a beautiful very large Monarch Butterfly. I was curious because i saw a circle sticker on its wing. I was able to get very close and read the phone number and the web site. It also had the number MLB048. SO if anyone is tracking this butterfly, that where i spotted him this morning.

  45. By Janie Tippins on Jul 14, 2010

    I would like to correspond with a fellow Monarch butterfly enthusiast in Wisconsin. I am not a scientist, just an observer desiring information & connection. I am raising a few.

  46. By deb on Jul 12, 2011

    Same thing this year. 2011. I’ve been searching my milkweeds for catapillars and haven’t found one yet. July 13. Where are they????

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