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.

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]

Sunday, September 16, 2018


It seems like every autumn one or more monarch enthusiasts bring monarch butterflies from elsewhere to Cape May.  We just learned that this happened again yesterday.  While this is based on good intentions, we strongly discourage this.  It's bad for our research project, it's bad for conservation, and it is bad for the monarchs.  It gets us very upset.  Let us explain.

1. Bad for science: Our study began in 1990, and we have conducted systematic censuses of monarch butterflies in Cape May since 1992.  Bringing monarchs from elsewhere to Cape May leads us to count more monarchs than are naturally finding their way to Cape May.

2. Bad for conservation: If we end up with counts of monarchs that are artificially high because of monarchs brought from elsewhere, our data can be used to argue against the need to conserve monarch habitat locally and regionally.  We've made a lot of progress on monarch conservation here in New Jersey, don't sabotage our work!

3. Bad for the monarchs: There is evidence to suggest that monarchs migrating along the coast have a lower survival rate than monarchs migrating along inland routes.  The major water crossings, such as Delaware Bay and the Chesapeake Bay, are dangerous for monarchs, and we know that many perish in their attempts to cross over from Cape May to Delaware.  Monarchs from further north in New Jersey, and especially monarchs from Pennsylvania (where we understand yesterday's "delivery" originated), are likely to migrate on the west side of our big coastal bays, and more are likely to succeed in the migration.  Bringing them to Cape May takes them from a safer environment into a more dangerous one.  Plus, we don't know if they'll properly orient themselves toward Mexico if they've been driven a hundred or more miles by car.

We ask all monarch enthusiasts to respect our nearly three decade study of monarchs and also trust that nature knows best -- a monarch should be given the chance to make its migration from the spot where its mother chose to lay her egg.  Please, please, do not transport monarchs from elsewhere to Cape May.

Friday, September 14, 2018

Waiting, waiting

We have experienced a full week with winds blowing from the east, along with at least a little bit of rain almost every day.  These are not conditions that bring migrating monarch butterflies into Cape May, and indeed it has been a very slow week for our team.  We held our first four "drop-in" programs at the Triangle Park, where there were few monarchs and even fewer human visitors.  We start up our second weekend of tagging demos at Cape May Point State Park, and with a weather forecast for continued east winds, clouds, and some more rain, we don't expect to have many monarchs to show our guests.  There should be a few -- we are seeing some monarchs each day, but we guess that these are mostly ones of local origin.

Sarah Crosby tags a monarch at last Saturday's demo.
Once the weather changes we expect to see migrating monarchs, and perhaps a lot of them.  We saw reports this week of huge numbers gathering at Point Pelee, Ontario, then flying across Lake Erie and gathering at various spots in northern Ohio to rest before continuing the trek to Mexico.  Many people from the midwest to New England and right here in New Jersey reported seeing lots of monarchs last summer, so we still expect to see large numbers in Cape May.  But as long as the winds are wrong and strong, alas, we don't expect to see them.

Lindsey Cathcart describes tagging to an enthusiastic group.
Many monarchs or few, we will continue with our public programs and we invite you to come join us.  Every Friday, Saturday, and Sunday through October 14 we will offer our full Monarch Talk and Tagging Demo at 2 pm.  This program is held under the East Shelter at Cape May Point State Park -- that's the covered pavilion next to the hawk watch platform.  On other days, Monday through Thursday, you can meet a member of our team at 1 pm at Cape May Point's Triangle Park, located at the junction of Lighthouse and Coral Avenues.  There is no fee for either program, though donations are accepted.

Saturday, September 8, 2018

First Demo, Status Update, Recovery Mystery

Our first tagging demo was held on Friday, Sept. 7, with a small but enthusiastic
audience.  Our 2018 field naturalists Lindsey Cathcart and Sarah Crosby did a great job showing groups all the details of monarch tagging, and our field coordinator Louise Zemaitis worked with a third group.  These demos continue each Friday, Saturday, and Sunday through Oct. 14, with more demos the following weekend as part of the Cape May Fall Festival.

Lindsey Cathcart

Sarah Crosby

Monarch numbers around Cape May are still modest, as recent warm weather has not brought migrants into our region.  We suspect that most of the monarchs we have been seeing began their lives nearby; we continue to see many eggs, caterpillars, and chrysalides in the gardens throughout southern New Jersey.

We did get one surprise on Friday: a previously tagged monarch was netted in Cape May Point at about 1:30 pm.  We have reported this find to the folks at Monarch Watch, who maintain the tagging database, but we're hoping someone who follows our project may have been the one to tag this butterfly.  The tag code, as seen below, is YBR 728.  Our project this year has been issued tag codes beginning with YBX, YBY, YBZ, YCA, YCB, and YCC.

We are often asked to predict when the biggest numbers of migrants can be seen in Cape May Point.  Sadly we can't predict, though we do know that cold weather fronts that bring northwest winds can often bring monarchs into Cape May.  One thing we can promise: we'll post quickly in the blog whenever we see the numbers of monarchs increasing here in Cape May.  In the meantime, we hope you'll come visit and attend one of our tagging demos.  A few more photos of our first demo are shown below.

Thursday, September 6, 2018

Programming begins Sept. 7

2018 Monarch programs begin on Friday, Sept. 7.  We will present our formal tagging demos every Friday, Saturday, and Sunday through Oct. 14. Meet our team at 2 pm at Cape May Point State Park, where we gather at the covered picnic pavilion next to the hawkwatch platform (the "East Shelter").  On Mondays through Thursdays you can join our team for an informal "drop-in" at 1 pm at Cape May Point's Triangle Park, located at the junction of Lighthouse and Coral Avenues.     There is no fee for either program, though we will happily accept contributions.

Saturday, September 1, 2018

Field Season Begins

September 1 marks the beginning of our field season each year.  Our team will conduct the season's first three censuses today, they'll begin tagging monarchs, and they'll begin to assess conditions in the gardens in and around Cape May Point.

We have been seeing fairly good numbers of monarchs all around Cape May recently.  In late August we see a mix of the year's first Mexico-bound migrants along with butterflies who are parenting that generation.  Anecdotal reports from the midwest to New England suggest that this could be a very good year for monarch migration.  Does this mean the numbers will be big in Cape May?  All we can say is maybe.  What we can say for sure is that our team will be out there every day, counting and observing, and we will report back to our followers about how the season is progressing.