The Monarch Monitoring Project is a long-term study on monarch migration through Cape May, NJ. It is a part of the New Jersey Audubon Research Department, and closely affiliated with the Cape May Bird Observatory.

Monday, December 24, 2018

First 2018 Recovery Data

Holiday greeting to all friends of the Cape May Monarch Monitoring Project.  The first reports have trickled in about monarchs tagged in Cape May during the 2018 fall migration and found elsewhere.  There are no reports from Mexico yet, that information always comes much later.  We are happy to report about five monarchs tagged here and found a significant distance away:

YCB 266, tagged 9/20/18 by Lu Daniels, found 10/13/18 in Savannah, GA
YCA 050, tagged 9/28/18 by Karen McClennen, found 101518 in Chapel Hill, NC
YCC 154, tagged 10/3/18 by Patsy Eickelberg, found 10/12/18 in Tabscott, VA
YBY 375, tagged 10/5/18 by Sarah Crosby, found 10/9/18 in New Market, MD
YCB 572, tagged 10/23/18 by Betty Ross, found 11/17/18 in Spring Hill, FL

We hope to receive data about many more of the monarchs tagged by our project this year.

Reports are coming in from Mexico that suggest a major increase in the number of monarchs being seen in the winter colonies.  While NJ Audubon does not have a Mexico trip planned for 2019, we are planning a trip for late February 2020, when we hope the numbers will also be big.

Monday, November 12, 2018

2018 Season Wrap Up

The 2018 monarch field season officially came to an end on November 7th. Traditionally, the censusing ends on October 31st, but because of some late pushes of monarchs last season we extended the censusing another week. We decided to extend the season again this year with the hopes of continuing in future years, as peak migration days have been getting later and later each year.
Now that all of the census data is in, we know that this season has been a bit below average. The average monarchs seen per hour was 47.1 in 2018, compared to the historical average of 69.9. Here are some stats from the field:
Monarchs roosting the evening of October 14h.
Spot the tagged monarch!
  • The peak migration day was October 3rd, where Lindsey counted 271 monarchs on the three censuses that day (271 monarchs per hour)!
  • The peak migration week averaged 137.41 monarchs per hour and was September 29th through October 5th. 
  • We reared 75 monarchs at our live caterpillar display at the Northwood Center this season.
  • The best roosts spotted were October 13th and 14th, with the biggest clusters being over 50 monarchs. 
  • The total monarchs tagged by everyone in the project was over 4,300!

Despite some below average monarch numbers, the season was still quite a success. We reached thousands of people with the message of monarch conservation through both State Park demos and informal meetings with passersby in the street while tagging monarchs. Peak days brought monarch-covered goldenrod on sunny afternoons, and roosts in the pitch pines in the evenings. In addition to monarchs, there were amazing migration days of American Kestrels, Common Buckeyes, various dragonflies, Saw-Whet Owls, and many other species. 

Below are some images from the 2018 field season:

A chrysalis found in our volunteer Pecki's yard,
she was sure to keep it safe until it emerged and
took off!

Small cluster of monarchs at the State Park warming
up to start their day

A female laying eggs on Common Milkweed
early on in the season
Common Buckeye on goldenrod, a very common migrant this season

We want to thank all of our volunteers, everyone involved with the project, all of those who attended our tagging demos and other events, the folks we met while out in the field who inquired about our work, the readers of the blog, as well as anyone and everyone who has a passion for helping conserve the wondrous little migrant that is the monarch butterfly.

It has been a wonderful fall season here in Cape May, and we are looking forward to hearing the reports from Mexico this winter with hopes of Cape May recoveries!

Wednesday, October 31, 2018

Surprising increase in monarchs

We had just about given hope of seeing many more monarchs in Cape May Point this year, since we have seen very low numbers over the last week.  Gentle northwest winds on Tuesday brought a modest increase in monarch numbers, to our surprise, and it seemed like numbers were increasing throughout the day.

While the seaside goldenrod is still blooming along the upper beach, the monarchs were not found there.  Maybe it was the wind -- the beach is always the breeziest spot -- or maybe the goldenrod isn't offering much nectar.  Thankfully there are many active gardens around Cape May Point that are still filled with nectar-rich flowers, and that's where the monarchs were found.  As a team we tagged nearly 100 monarchs today.

We don't know what's going to happen over the next few days, but the weather is supposed to stay fairly mild, so one more late surge of migrating monarchs may be possible.

We were also surprised today by good numbers of other butterflies.  We saw a sudden upsurge of Red Admirals, including the one shown above, and there were several other species found in the gardens around Cape May Point.  The fresh Question Mark, shown below, was certainly one of the most beautiful.

Sunday, October 21, 2018

Fall Festival Wrap Up

This past weekend, October 19th - 21st, the Cape May Bird Observatory hosted the annual New Jersey Audubon Fall Festival, a celebration of all things migration. Our team had the pleasure of setting up a display at the Cape May Convention Hall, where we were fortunate to meet hundreds of visitors and share the magic of the monarchs.

Two chrysalises emerged during the festival weekend! As usual, this happened when no one was watching.

If you missed our tagging demonstrations and are still looking to see the process in action, this upcoming week (10/22 - 10/25) will be our final week of Triangle Park drop in days. Come to Triangle Park at 1:00 PM Monday through Thursday to send off the final waves of monarchs down to Mexico.  Triangle Park is located at the junction of Lighthouse and Coral Avenues in Cape May Point.

To those of you we met at the festival, thank you for stopping by. We were very pleased to sell out of milkweed seeds and hear about all of the work being done to promote monarch conservation, from gardeners with milkweed patches and nectar sources, to educators who bring caterpillars into their classrooms everyday. Our project relies on folks like you who are truly making a positive impact on the monarchs. We hope to see you at the festival next year!

[Post by Naturalist Lindsey Cathcart]

Sunday, October 14, 2018

Monarch numbers increased on Sunday

We were growing impatient in Cape May, as we heard reports of good numbers on monarchs in Ocean City and Stone Harbor over the last few days, two spots north of us in Cape May County.  Numbers had remained fairly modest here in Cape May Point.  On Sunday they finally started to arrive, and we enjoyed a nice influx of monarchs.

Most of the monarch activity was on the seaside goldenrod, which is now at peak bloom.  Monarchs and goldenrods are easy to see right now along the trails near the dunes at Cape May Point State Park, along the promenade in Cape May City, next to many of the dune crossings at Cape May Point, and in a variety of other locations here at New Jersey's southern tip.

We wondered if monarchs might gather into roosting groups this evening.  When the weather is chilly at night this often happens, and at times in the past we have seen aggregations of many hundreds, even thousands infrequently.  The weather didn't cool much as sunset approached, and many monarchs looked like they would settle in for the night right in the goldenrod patches, but some did fly up into conifer trees near the beach, with a little more than 200 counted shortly before sunset along the trail to the beach across from St. Peter's Church, at the Intersection of Harvard, Ocean, and Lake.  We think that there are more monarchs on their way to Cape May Point over the next day or two, but we can't be sure, and we don't know how long those that arrived on Sunday might stick around.  We'll just have to head out again tomorrow and see what we find.

Friday, October 12, 2018

Looking good for Saturday

A big cold front passed through Cape May Thursday night into Friday morning, bringing strong northwest winds onto the Cape.  Northwest winds trigger all sorts of migration, and more than 5,000 American Kestrels (shown here) were counted from the Cape May hawkwatch on Friday.  Northwest winds are the best for monarch migration, but we saw very few here on Friday -- the winds were just too strong.  Lighter northwest winds are predicted for Saturday, and we have received reports of many monarchs occurring on Friday at Stone Harbor, just 10 miles to the north of us, so there are many reasons to expect a lot of monarchs in Cape May on Saturday.  Come see us if you can -- we'll offer our regular monarch talk and tagging demo at 2 pm in Cape May Point State Park, under the East Picnic Shelter (adjacent to the big hawkwatch platform, across the parking lot from the lighthouse).

Newly tagged monarch takes off from a visitor's hand
at Friday Monarch Tagging Demo.

Wednesday, October 10, 2018

Uncertainly lies ahead

Seaside Goldenrod as seen from the St. Peter's dune walkway, Cape May Point.

Monarch numbers have been modest around Cape May Point this week.  Witness the Seaside Goldenrod along the dunes, as seen above, a favorite nectar source for migrating monarchs.  Only a few monarch have been seen enjoying these nectar-rich flowers.

The current weather forecast shows the edge of Hurricane Michael swinging through Cape May in the near future.  Tropical storms are notoriously hard to predict, but it seems certain that we'll get some effect from this system.  Rain seems almost certain, but if the storms trends south it could just be ¼ or ½ inch, while if it veers a bit further north we could get 4 inches or more.  Some high winds also seem likely, with stronger winds likely to occur if the storm takes the more northerly track.  Most impacts of the storm look like they'll be here between Thursday afternoon and Friday morning.

A strong cold front is predicted to usher the storm out to see, bringing much cooler temperatures and strong northwest winds for the weekend.  Northwest winds are generally the best for monarch migration into Cape May, but the butterflies don't do well in especially strong winds nor in heavy rain.  So we are more confused than ever about the prospects for monarch migration over the weekend.  We've just got to wait and see.

One thing is certain -- this Friday through Sunday, Oct. 12 -14, we'll have our last formal tagging demos at Cape May Point State Park, each starting at 2 pm at the park's East Shelter.  Last Saturday we hosted about 140 people at this program, we're hoping that even more of you will come to see us this weekend!  On the following weekend, Oct. 19 - 21, we'll be participating in the NJ Audubon Fall Festival, with a table at the Cape May Convention Hall and tagging demos at noon on Saturday and Sunday (and perhaps impromptu demos at other times).  You can also meet one of our team members each Monday through Thursday, through Oct. 27, at 1 pm at Cape May Point's Triangle Park (at the junction of Lighthouse and Coral Aves.) for a casual chat about monarch biology and conservation.

Common Buckeyes are still abundant around Cape May Point.
At least these lovely butterflies are enjoying the goldenrod!

Sunday, October 7, 2018

Cape May Monarch Festival today!

The Nature Center of Cape May hosts the annual Monarch Festival today, Sunday Oct. 7.  Our team will be there for tagging demos and an illustrated talk on monarch biology and conservation.  We hope to see you there!  Details here:

Friday, October 5, 2018


Finally, we have had some impressive monarch days in Cape May! This week we have had census numbers exceeding the rest of the season by large margins, with Friday morning's census being our highest yet: 105 monarchs in 20 minutes. The seaside goldenrod has begun to bloom as well, a favorite nectar source for our fall migrants. Keep a look out for monarchs nectaring on the dunes across the point in the weeks to come! 

With this increase in butterflies, we also have more visitors attending our weekend tagging demonstrations (2:00 at the State Park, Friday to Sunday through Oct. 14) One of the things we will always suggest to help monarch populations at these demos is to plant milkweed anywhere and everywhere. Since milkweed is the only plant a monarch caterpillar can eat, they are absolutely necessary for monarch butterflies. Because of this, milkweed has become synonymous with monarchs.

Milkweed is also a host plant for a wide variety of other insects. Planting a milkweed patch creates an entire community of organisms that both depend on the milkweed and each other for survival. If you have a patch of milkweed at home, keep a lookout for these other milkweed dependent bugs, and you can start to look at the milkweed patch not only as food for monarchs, but as a village with many different residents!

Large milkweed bug

  • They do not eat the leaves of the milkweed plant, but use the seeds as their food source
  • Certain populations of large milkweed bugs are migratory, while others are not
  • Like the monarch, the large milkweed bug is toxic to predators

Milkweed leaf beetle

  • While milkweed is a major host plant for these beetles, they also will use some other plants in the larger milkweed family

  • Milkweed aphids

    • Aphids, in small colonies, are very unlikely to cause significant harm on your milkweed plant
    • Unlike most other insects, they give birth to live young
    • Female aphids are able to reproduce without a male, and if needed, one could create hundreds of clones of herself

    Milkweed tussock moth

    • Another milkweed caterpillar, the milkweed tussock moth gains its toxicity to predators from the host plant and retains it to adulthood
    • Like the viceroy butterfly, these caterpillars are a Mullerian mimic of monarch caterpillars

    [Post by Field Naturalist Sarah Crosby]

    Weekend Update

    Monarchs have been drifting out of Cape May over the last two days, and while there are still reasonable numbers around, more are likely to head across the Bay over the weekend. How many new ones will arrive? The migration will continue for a few more weeks, and certainly more monarchs are on their way, but it's impossible to predict when the next big surge will arrive. Wins are expected to blow from the east or from the south over the next few days, and those winds don't typically bring a lot of monarchs onto the Cape, but the usually patterns haven't been holding this year. We'll just have to wait and see.

    Tuesday, October 2, 2018

    Update 10/2/18

    Monarch numbers around Cape May Point seemed to drop gradually over the last few days.  Monday, late in the afternoon, I was netting a few monarchs to tag and many had already been tagged by another member of our team.  The fat measurement on most was high, suggesting they had been feeding, not traveling, over the last few days.  It seems that many other monarchs had crossed Delaware Bay and continued on their southbound migrations.

    Tuesday afternoon, however, I netted several monarchs and most had little or no fat reserve, suggesting that they had been traveling.  This hints at the beginning of another movement of monarchs into Cape May.  We also learned that big numbers of monarchs were seen today at East Point, about 30 miles to our north and another location where migrating monarchs often concentrate.  Typically we have 4 to 6 distinct surges of migrant monarchs into Cape May each fall, so another build-up of numbers is expected.  We're hoping that numbers will increase over the next few days, but we never really know what's going to happen.

    The discovery of monarchs tagged by someone other than our team is always unexpected, and we're delighted when it happens.  Sometimes the tagger came to Cape May -- that's why we ask all visiting taggers to share their tag numbers with us -- but sometimes they come from far away.  Today such a monarch was found, bearing tag code XYW 162.  We hope to learn soon the details of this tagging -- when and where it was tagged.

    Most of the monarchs that I saw today, as has been true for many monarchs over the last few days, were nectaring on the flowers of groundsel-tree, Baccharis halimifolia.  This native shrub is widespread around Cape May and other coastal areas in the east, and it attracts monarchs and many other insects when it's in bloom (see below).

    Unfortunately, the bloom period for groundsel-tree is brief, usually just for a week or less.  It won't be long before these blossoms are finished for the year.  Fortunately, just as its bloom period finishes, the next great nectar source becomes available.  Seaside goldenrod is abundant along the dunes and nearby patches of sandy soil around Cape May Point.  While most of the seaside goldenrod is still in bud, the first few flowers have opened up and the rest should come into bloom within the next few days.  For most of the month of October these flowers will be providing nectar for migrating monarchs.

    Seaside goldenrod in bud (left)
    and beginning to bloom (above).

    We hope that we'll see many visitors coming to Cape May over the next few weeks, and we hope that there will be plenty of monarchs for those visitors to enjoy.  Watch for other butterflies while you're here, perhaps you'll see a gray hairstreak, a common buckeye (they're exceptionally common this fall), or the scarce long-tailed skipper.  There's always plenty to see on a visit to Cape May.

    Gray hairstreak

    Common buckeye
    Long-tailed skipper

    Saturday, September 29, 2018

    Monarch updates and the caterpillars of Cape May

    Migratory activity has been finally speeding up for the season, and our team is very eager to be out and about on the point with monarchs abounding. Typical for this time of the season, fewer are being found nectaring on thoroughwort while more and more are choosing to feed off of butterfly bush. This transition will continue, and eventually seaside goldenrod will provide nectar for migrating monarchs. 

    With falcons soaring and diving across the point, Friday's cloudy weather and strong winds put a temporary halt on monarch activity in Cape May. However, this was the perfect opportunity to go out and find monarchs in their other stages of metamorphosis. 

    In addition to tagging migratory monarchs, the MMP also raises a small number of monarchs from eggs and caterpillars at the Cape May Bird Observatory's Northwood Center. If you're in the area, it is definitely worth coming to check out our tanks, where eggs are hatching and caterpillars are demolishing fresh milkweed faster than we can supply it. It is a bustling terrarium, and if you're lucky, maybe you'll see a caterpillar pupate, or a chrysalis eclose. 

    When the tagging has been slow, in our daily travels Sarah and I have come across an interesting array of other caterpillars we'd like to share. 

    An early instar black swallowtail caterpillar (Papilio polyxenes) feeding on increasingly bare stems of dill. They are commonly found in gardens because they feed on the leaves of parsley, dill, carrots, fennel, and other related plants. If you see them form chrysalises, don't move them indoors because unlike monarchs they will overwinter locally as pupa.

    A snowberry clearwing (Hemaris diffinis) feeding on its host plant, a native honeysuckle. As adults, these moths are day flying nectar feeders and will often be seen at the same flowers as the monarchs. 

    Brazilian skippers are here in Cape May! While they are typically restricted to Florida and Texas, they will occasionally make their way north into Cape May. If you seen Canna leaves rolled up, they are probably tucked away inside to hide from predators.

    A personal favorite - the saddleback caterpillar (Acharia stimulea) was found in a garden on Canna. You can look, but don't touch, because they are covered in urticating hairs that can cause a painful sting and lasting reaction. They belong to a family of moths called the slug moths, named for their strange often sluglike appearances. 

    A snake on the monarch blog? Not today - this is the clever spicebush swallowtail (Papilio troilus). Their bright eyespots are used to scare away birds, due to their resemblance to snakes. They can be found on their namesake spicebush, in addition to sassafrass and sweet bay. 

    And finally, we couldn't wrap up the blog without including the monarch caterpillar. For as often as they are seen, they never lose their magic in enticing folks of all ages and backgrounds into the world of wildlife. Their thick yellow, black, and white bands can be surprisingly well hidden below leaves of milkweed, but if you turn over enough leaves, you're bound to be rewarded with a look at one of these charismatic creatures. 
    Happy caterpillaring!

    [Post by 2018 Field Naturalist Lindsey Cathcart]

    Friday, September 28, 2018

    Weekend Outlook

    Monarch numbers around Cape May continued to be good on Thursday. Heavy rains overnight may have had a bit of a negative impact, but favorable winds are predicted and we are hopeful. We know better than to make bold predictions, the butterflies fool us sometimes, but the numbers could go up over the next few days.

    Do you tag monarchs?  If you plan to tag monarchs in Cape May, please let us know and coordinate your efforts with us.  We like to keep track of the total number of monarchs tagged in Cape May -- percentage of tagged monarchs recovered in Mexico is a data point that proving to be very useful in research studies.  We also request that taggers avoid working in areas along our census driving route while the census is taking place -- that can skew our data.  If you don't know the route, just avoid netting or disturbing butterflies during these intervals: 9:00 - 9:30 am, noon - 12:30 pm, and 3:00 - 3:30 pm.  Finally, remember that explicit permission is needed to net butterflies in parks, nature conservancy preserves, and private property, not just in Cape May but everywhere, and that you should never walk onto the dunes or the vegetated upper beach in Cape May Point.  Thanks in advance!

    Did you tag YSB 206? If so, please let us know
    when and where it was tagged.

    Tuesday, September 25, 2018

    Monarch numbers have increased

    Monarch numbers are up!  It's the best day of the season so far, with good numbers all around the Cape.  Not massive numbers like we see some years -- we're still hoping that will happen this year -- but the best so far.  A bit of a surprise given that winds are blowing from the southeast.  We don't know if this is a temporary increase or if the numbers will continue to climb in the days ahead, but we promise to report back either way.

    Saturday, September 22, 2018

    Equinox update

    The autumnal equinox has arrived, and over the last three days a modest number of migrating monarchs have flown into Cape May, but the overall numbers remain low.  We are receiving a lot of questions for people who want to visit Cape May Point to see monarchs.  If you've never been here before, and if you've never been to another migratory concentration point when the butterflies have been abundant, you'll probably be quite satisfied with a visit right now.  Monarchs are being seen in many locations around the Point, from the trails at Cape May Point State Park to the private gardens in the residential area.  Stroll around and you'll probably see dozens of monarchs.

    Monarch along the trail at Cape May Point State Park.
    If you've been to Cape May when monarchs are everywhere, however, we want to point out that it's not like that right now, and we haven't seen the first day of this migration season when the butterflies have been here in abundance.  We expect that to happen sometime, but we can't guess when, other than to say that it usually happens after winds have switched to the northwest.  Will it happen this weekend?  It's possible, the winds are shifting today and we expect an hour or two with northwest winds, but there's a better chance that the numbers will remain fairly modest.

    Field Naturalist Lindsey Cathcart discusses monarch
    migration at the tagging demo 9/21/18.

    There is something we can promise: each day this weekend, and every Friday, Saturday, and Sunday through Oct. 14, our Field Naturalists and volunteers will present one of our Monarch Tagging Demos at 2:00 pm in Cape May Point State Park.  There is no fee for these programs, which are held under the east picnic shelter in the park (that's the one next to the Hawk Watch Platform).

    Good numbers of Ospreys have been migrating over Cape May Point.

    Since we mentioned the Hawk Watch, it's worth noting that there are many reasons for nature enthusiasts to visit Cape May Point at this season.  One of the most popular activities is watching the hawk migration.  Monarch numbers have been modest so far this year, but every day in Cape May is rewarding for lovers of nature.

    Tuesday, September 18, 2018

    Monarchs and Mimicry: The Viceroy Butterfly

    With all of the strange weather and eastern winds, the monarch migration still hasn't really gotten started here in Cape May. If the forecast stays the same, next Wednesday (Sept. 19th) is looking good for weather and winds. Fingers crossed for an influx of migrants! Until then, I wanted to share some images and information on a monarch butterfly lookalike, or mimic: the viceroy butterfly.

    Monarch on Butterflybush

    Mimicry in the Animal Kingdom 

    For many years, it was thought that viceroy butterflies were Batesian mimics of monarchs. Batesian mimicry is when a palatable species evolves to resemble an unpalatable species to avoid being eaten. Since they are not poisonous themselves, they can at least appear to be so in order to “trick” predators into thinking they are the poisonous species they evolved to look like.

    However, in recent studies, it was found that the viceroy butterfly is in fact unpalatable to predators. When caterpillars, viceroys eat plants in the willow family (Salicaceae) and keep the salicylic acids in their bodies through adulthood, which makes them inedible to vertebrate predators. Monarchs, as many may know, do the same with sequestering toxins out of milkweed. Since both butterflies are toxic to vertebrate predators, their relationship is no longer Batesian mimicry. This type of mimicry is known as Mullerian mimicry, where both species are unpalatable and evolved to mimic each other. This is an advantage for both species since fewer individuals of a species have to die in order for the predators to learn to avoid them.

    Telling Apart Monarchs and Viceroys

    To tell the difference between a monarch (image below on left) and viceroy (image below on right), there are multiple things you can look at. What you will likely notice first is the size difference. Monarchs have a wingspan between 94 and 105mm, and viceroys have a wingspan between 53 and 81mm. These butterflies do not need to be seen up close to notice this size difference, and the images below help emphasize how much larger the monarchs really are.

    Even though the butterflies share the same coloration, the patterns of the dark lines differ in each of the wings. On the outsides of the hind wings, viceroys have an additional black line going perpendicular across all of the radial lines. Monarchs lack that perpendicular black vein. This additional line on the viceroy is the most distinctive difference between these mimics.



    [Post by Field Naturalist Sarah Crosby]