Season Update, September 27, 2020

It's been a while since our last post, and we apologize for that, but we're starting to get busy with monarchs in Cape May Point.  The weather changed abruptly on September 18, with cooler temperatures and winds blowing from the north.  North winds trigger migration, but most monarchs come into Cape May when there's also a westerly component, and for 4 days we had winds from the northeast.  We saw some influx of monarchs into Cape May, certainly more than we had seen earlier in the season, but the numbers really picked up over the last 3 days.  Gentle northeast winds today triggered an exodus, as many headed out across the Bay towards Delaware, but there's still no shortage of monarchs at Cape May Point. South winds are predicted for Monday and Tuesday, and while that's not likely to bring many more monarchs into Cape May, the ones that are here aren't likely to leave.

Monarchs at Cape May Point, 9/27/20

That should all change Wednesday, if the forecast holds, when the next cold front is predicted to arrive bringing northwest winds and, with luck, a big influx of migrating birds and monarchs.  Another front is predicted to arrive on Friday, meaning we could be in for several excellent days for viewing monarchs throughout southern New Jersey.  Most of our work is focused on Cape May Point, and we suggest that monarch fans visit the public gardens at Pavilion Circle, the south end of Lake Lily, Triangle Park, and Cape May Point State Park -- all can be very good spots for viewing monarchs.  

Monarchs at the south end of Lake Lily, Cape May Point

The next week will bring the beginning of the bloom period for seaside goldenrod, a great nectar source that is widespread in the dunes.  You can observe from the beach or one of the dune crossover trails, but never walk into the dunes away from the paths -- footsteps can quickly turn into erosion on these sandy structures, and the dunes are crucial for protecting coastal areas from storm tides and floods.

Monarch on seaside goldenrod, Cape May Point dunes, 2019

There are many other places where monarchs concentrate in southern New Jersey.  The south end of the barrier islands along the Atlantic coast are often excellent, places like the Two Mile Beach Unit of the Cape May National Wildlife Refuge and Stone Harbor Point.  There are some great spots along the Delaware Bay shore as well, with East Point, at the mouth of the Maurice River in Cumberland County, a particularly good location.  Any meadow filled with fall-blooming flowers can be good, such as the meadow filled with tall goldenrod at the Garrett Family Preserve, where our team is conducting monarch programs on Friday and Saturday afternoons this fall.  Find information about registering for our programs here: https://njaudubon.org/event/monarch-biology-5/.  Pay careful attention to the directions if you do sign up, some folks have had trouble finding this hidden gem of a nature reserve, which is owned and operated by The Nature Conservancy. 

Meadow filled with tall goldenrod at the Garrett Family Preserve

Our team has been tagging lots of monarchs, so it's time for our annual reminders about tagging monarchs.  If you see a monarch with a tag, try to read the code that's the final line on the tag, consisting of 4 letters and 3 numbers.  On the monarch shown below, that code is ACBA 170.  Often a digital photo can be enlarged on the computer and the tag code can be read.  Visit the web address shown on the tag, mwtag.org, and fill out the form with the date and location of your find, and you'll be making a big contribution to our understanding of monarch migration.

Monarch ACBA 170, tagged at Cape May Point

We know that there are other monarch enthusiasts who tag -- anyone who is interested can purchase tags from Monarch Watch, and there's no special license required.  If you're a tagger and you're not part of our project, we'd suggest visiting one of the other sites listed above, as we have Cape May Point well covered, but if you do tag here, we ask that you share your tagging data so we can include your tagging numbers with our long-term data set.  Many thanks!

Monarch Life Cycle

 Director's Note: Our two seasonal naturalists for 2020, Katherine Culbertson and Jack McDonough, are preparing a series of blog posts designed to educate readers about many aspects of monarch biology and related topics.  Here's the third of this series, written by Katherine Culbertson, with photos by Katherine (except chrysalis and Mexico photos by Mark Garland), and titled: 

Monarch Life Cycle

We’re all familiar with adult monarchs – the beautiful black-and-orange butterflies flitting around Cape May right now, sipping nectar out of flowers. But this is only part of their amazing life cycle – and a small fraction of the life of most non-migratory generations. 

Adult female monarch butterfly

Monarch egg

Monarchs start life as a tiny egg laid on a milkweed leaf. Every female monarch will lay around 100-300 eggs in her lifetime, each on its own individual leaf. Milkweeds, plants of the genus Asclepias, are the host plants for monarchs; their caterpillars won’t eat anything else. There are 73 species of milkweeds native to the U.S., of which about 30 are known to be used by monarchs. These plants can vary widely in appearance, ranging from the large broad leaves of the common milkweed to the narrower, pointy leaves of butterfly weed and swamp milkweed, and to the vine-like climbing milkweed.

Newly hatched monarch caterpillar

After about 4-6 days monarch eggs hatch into tiny caterpillars. A newly hatched caterpillar doesn’t have its bright yellow, black, and white banded pattern yet; it also isn’t poisonous yet, as it hasn’t eaten enough milkweed. As the caterpillar grows, its striking colors become more defined. This coloration serves as a warning to birds and other would-be predators that monarchs do not make a good snack – they sequester a toxin from the milkweed they feed on that is toxic to any vertebrates that might try to eat them. A caterpillar’s only job is to eat; and eat, eat, eat, they do! From the time they hatch to when they form their chrysalis – a mere 10-14 days – a monarch caterpillar will increase in size more than a thousand-fold. For comparison, that’s like if a human baby, born at 8lbs, grew to be the size of an Asian Elephant in two weeks! As they grow, monarchs must shed their exoskeleton; that is, they must discard the tough chitinous material that covers their bodies to allow them to continue growing. This process is called molting. Each time a monarch molts, it transitions to a new stage called an instar. Monarch caterpillars molt 5 times during their lives, and thus have 5 instars.

Fifth instar monarch caterpillar

When monarchs have reached their 5th instar, after about two weeks of eating and growing, they are ready to pupate – to form a chrysalis, within which they will go through the process of metamorphosis, transforming into an adult butterfly. Once the 5th instar caterpillars become ready to pupate, they get the urge to wander until they find a suitable, protected place to form their chrysalis. Once they have selected a site, they attach themselves to that spot with silk, and hang upside down in a “J” shape. Soon, they molt a final time, and their appearance has completely changed – gone is the black, white, and yellow striped caterpillar, and in its place, an emerald green chrysalis hangs, decorated with gold “jewels”. The chrysalis may look dormant, but much is happening inside. The various parts of the adult butterfly – legs, wings, and other things – have already started growing within the large, fleshy body of the caterpillar, but now they continue to develop and rearrange within the chrysalis to assemble the adult butterfly. 

Monarch chrysalis 

After about two weeks, the chrysalis will start to change color, shifting from emerald green to a dark, purple-black tone; the bright orange of the butterfly’s wings starts to show through, as well. The butterfly is almost ready to emerge! Soon, the bottom of the chrysalis splits open, and out crawls the fully formed butterfly. At first, the butterfly’s wings are wet and crumpled, and the newly emerged butterfly must wait for them to expand and dry out before taking its first flight. Its proboscis – the straw-like mouth that allows it to suck nectar out of flowers – also isn’t properly formed yet when it hatches out. The two sides of the proboscis must “zip” together after it hatches out. Once the butterfly’s wings have dried, you can tell whether they are male or female – the males have an elongated black patch on both of their rear wings, which produces chemicals used in courtship by many species of butterflies. Females don’t have these patches, and also tend to be slightly darker and smaller than males, with thicker black wing veins.

Adult male monarch

Mating monarchs

Most monarch adults only live about 2-5 weeks, and don’t migrate long distances. Every summer, 3 or 4 generations of these non-migratory monarchs hatch out, migrating relatively short distances as the weather warms and their summer range expands. They mate and lay eggs along the way, parenting the next generation of monarchs. The final generation of the year, however, has a completely different life in store! As the fall approaches, something – no one is sure exactly what – causes this final generation to delay their reproduction and start migrating south. These are the butterflies that will fly hundreds, perhaps more than two thousand miles, and overwinter in Mexico. As they travel, the nectar they drink from flowers allows them to build up enough fat reserves to spend the winter dormant in Mexico. Unlike the previous generations, they will live 6 to 9 months, and in the spring, they will reawaken, mate, and lay eggs as they start to venture north, beginning the first generation of summer monarchs for the next year.

Monarchs starting to head north from Mexico wintering grounds

Monarchs and Viceroys

Director's Note: Our two seasonal naturalists for 2020, Katherine Culbertson and Jack McDonough, are preparing a series of blog posts designed to educate readers about many aspects of monarch biology and related topics.  Here's the second of this series, written by Jack McDonough, with photos by Jack, and titled: 

Monarchs and Viceroys: A Tale of Mimicry

    Migrating Monarchs, look, they’re all around us! Or are they? What if I told you that there are imposters out there, wanna be butterflies who wish they could be as awesome as the Monarch, so they dress up as Monarchs to steal all their praise and glory. Thousands of Monarchs in Cape May suffer every year from identity theft by Viceroys, taking a huge toll on their credibility as butterflies. Person after person will come along and take photos of Monarchs, admiring them for their intense migration and nobility, when in reality, it's just a vile Viceroy in disguise! Help save the Monarch community in restoring their respect by educating yourself below. Together, we can expose the criminal activity of the vile Viceroys and win back the mighty Monarchs title of being the best butterfly.

     Viceroys (Limenitis archippus) are Monarch mimics, even though they're not very closely related.  The mimicry of Viceroys was originally referred to as Batesian mimicry, named for Henry Walter Bates, who in 1862 discovered that some species falsely mimic the aposematism of other species (found commonly in snakes, plants, and in multiple species of butterflies). Aposematism is the term biologists use when species have bright flashy colors (usually red or orange paired with black) that warns predators that they are distasteful or toxic to eat. Upon seeing these bright colors, predators leave them alone. Monarchs are toxic to invertebrates, so any mammal or bird that might wish to take a bite into a Monarch will quickly regret the decision. However, it has been recently discovered that Viceroys are, in fact, toxic as well, having evolved a different kind of toxin than Monarchs. So this is actually called Müllerian co-mimicry and not the Batesian mimicry as previously thought. Müllerian mimicry is when two or more species evolve similar appearances when both toxicity and/or foul taste, so that a lesser toll is taken on each species by predators who are still learning to avoid that appearance. By looking almost the same and both being toxic partners, the two species (in this case the Monarch and the Viceroy) both benefit from each other. However, because of this evolutionary adaptation, they’re often hard to distinguish. Sneaky, but not sneaky enough to get past our naturalists here at the Monarch Monitoring Project! Viceroys can be detected by the thin black line that up-curves across the hind wing of the butterfly that Monarchs do not possess. Viceroys also tend to be smaller and a little brighter in color. Unlike Monarchs, Viceroys do not migrate, and they breed on willow, as opposed to milkweed. Viceroy caterpillars can survive winter as caterpillars, and they have much more stable numbers since they don't need to take long migratory journeys.   

The Viceroy practices Müllerian mimicry with the Monarch to increase its survival chances

Monarchs have bright orange color to alert potential predators of their toxicity; this communicative warning is called aposematism

    If you thought the story ended there, look again: even the caterpillars can be deceptive! Black Swallowtails (Papilio polyxenes) have caterpillars that can look very similar to that of Monarchs. The easiest way to tell the difference between Black Swallowtail and Monarch caterpillars is to note that Monarch caterpillars have filaments off their front and rear that appear as a type of attennae, while swallowtails do not have this. Monarchs are stripped with black, white, and yellow; swallowtails are more spotted in design with black and yellow, lacking white. Swallowtails are also much chubbier, especially at the head. Then, if all else fails and you get confused, or are unsure, just remember the host plant. Monarchs only breed on milkweed, whereas Black Swallowtails lay eggs on parsley, as well as carrot, celery, dill, and fennel. So if you have a big plump green caterpillar in your vegetable garden, it’s most likely a Black Swallowtail. 

Monarch caterpillar on Common Milkweed

Black Swallowtail caterpillar on parsley

Census Results, Week 1

Those of you who have followed the Monarch Monitoring Project for a while are aware of the daily censuses that our team conducts between Sept. 1 and Oct. 31.  This is year 29 for our census, surely making it one of the longest duration quantitative surveys of monarchs that's ever been conducted.  We summarize the census by weeks, and during this year's first week (Sept. 1 - 7), the average was 12.5 monarchs sighted per hour (see chart, below).  This ranks 18th for week 1, meaning 17 years have seen a higher average and 11 have seen a lower one.  It's still too early to predict if the whole season will be above or below the long term average, which is why we continue to count monarchs several times, every single day, during our two month field season.

We want to remind monarch enthusiasts who raise monarchs inside that it's always best to release them into the wild at the same location where they first emerge.  Every year we see well-meaning people bring monarchs to Cape May Point for release.  There's evidence that moving recently emerged monarchs impairs their navigational ability.  It's also very true that Cape May can be a hazardous place for monarchs, as the dozen miles of ocean water between Cape May and Cape Henlopen in Delaware is a very difficult trek for a monarch butterfly, especially one that's been moved here from elsewhere.  Finally, bringing monarchs to Cape May can impact our long-term census.  So please, release your monarchs where you raise them.

Little Butterfly, Big Journey

Director's Note: Our two seasonal naturalists for 2020, Katherine Culbertson and Jack McDonough, are preparing a series of blog posts designed to educate readers about many aspects of monarch biology and related topics.  We will still post updates and summaries on the state of the migration through Cape May, but we hope readers will find these additional posts to be both interesting and informative.  The first from this series was written by Katherine Culbertson, titled: 

Little Butterfly, Big Journey: A little bit about monarch migration and why it matters

Monarch in flight, photo by Jack McDonough

Monarchs are starting to roll through Cape May on their fall migration! While we’re still a ways out from the peak of their migration, monarchs are becoming more commonplace around the Cape, especially in some of the most elaborate native flower gardens. But where did they come from? And where are they going? And why on earth does it matter? Chances are many of you already know the answers to these questions, but to get everyone up to speed, this blog piece – the first in a series of educational blog posts on monarchs – will set out to address these questions.

As you likely know, monarchs embark on a seasonal migration through North America each year. Most of the population will overwinter in Mexico, heading north as the weather warms in spring, and returning back south as cooler fall weather approaches again. However, no individual monarch will make the entire migration to Mexico and back; in fact, monarchs complete this journey over at least four generations! During the first four generations, the entire population migrates to the north, taking advantage of the expanding plentiful seasonal milkweed (caterpillar food) and nectar resources (butterfly food) of temperate climates. As the weather starts to change in the fall, the year's final generation – the monarch “super generation” – is born. These butterflies will make the journey all the way from their summer feeding grounds to overwintering sites in Mexico. They travel an average of 50 miles per day on their journey and live nearly 8 times longer than all of the previous generations. Of the monarchs you’re seeing now, some are still part of the last summer generation, which won’t actually make it to Mexico; their children, however, will. 

Monarch migration map courtesy of Monarch Watch

The migratory monarchs you are beginning to see now likely hatched out in coastal areas of the U.S. and Canada northeast of Cape May – places including New Brunswick, New England, and the eastern part of New York and Pennsylvania, or perhaps right here in New Jersey. Because the northeast part of North America tapers west as it goes south, many monarchs from the northeast regions travel due south until they reach the coast, and then continue to follow it as it tapers into Cape May, creating a sort of natural funnel for the butterflies. (This is the same reason that Cape May is an incredible birding spot, too!)

Some of the butterflies tagged here in Cape May in the past – at least 90 so far – have made it all the way to Mexico and been recovered there! Our butterflies have been found in several southern states along the flight path to Mexico, too, including Virginia, South Carolina, and Texas. Interestingly, some have ended up in Florida, as well, possibly assimilating into the year-round populations found there. It’s unclear why some monarchs from Cape May end up in Florida, while others make it to Mexico. Did those in Florida end up there intentionally? Or did they simply lose their way on their journey to Mexico, or get detected there en route? Scientists are still trying to figure this out!

Roosting monarchs at Cerro Pelon Sanctuary, Mexico. Photo by Mark S. Garland

Now, the question you’ve all been waiting for: Why is it important to track migrating monarchs? Every monarch enthusiast may have their own unique answers, but I’d contend that tracking monarchs is important for two main reasons: First, monarchs serve as great biological indicator species; second, they are great science education “ambassadors”. 

As an indicator species, tracking the health of monarch populations can help us assess the health of the broader ecosystems they depend on. Because monarch populations need a vast expanse of habitat to successfully complete their multigenerational migration, they are one of the first species to suffer from habitat degradation and fragmentation. They are also easy to see and track, unlike many other less visible species dependent on the same habitat. A decline in monarch populations indicates that something is going wrong across the North American landscape, hopefully motivating actions to improve conservation and habitat restoration before many species are adversely affected.

Katherine Culbertson at age 8, photo by Chris Culbertson

As a “science ambassador”, monarchs hold the power to help people of all ages learn about our incredible natural world. Monarchs are easy to spot, can be found throughout the United States, are easy to raise, and venture on a truly incredible and inspirational journey. We don’t have to go out of our way to encounter them, monarchs can help teach us about migration, conservation, metamorphosis, and so many other things right in our very own backyards and nearby parks. We can all participate in tracking monarchs, too, through the Monarch Watch and Journey North nationwide citizen science projects. It’s especially magical for children to get involved in raising and providing habitat for these butterflies, generating a deeper understanding of and appreciation for nature. I, for one, can trace my love of science and nature back to my childhood adventures raising many a monarch caterpillar! It’s truly incredible to think a creature so small can travel so far – quite an inspiration for all of us, and a marvel of one of the many mysteries of the natural world! 

Monarch Programs at Cape May, Fall 2020

 

The COVID-19 safety restrictions are severely limiting the number and type of program we can offer this fall, but there are a few opportunities to formally connect with our team this fall, listed below.  As in other years, however, there are also informal opportunities to learn about monarchs and the work of our project and to see the butterflies up close.  If you're traveling around Cape May Point and see someone with a butterfly net, it should be someone working with our project, and they'll be happy to talk about monarch biology and research with you.  We do ask that you follow all of the COVID-19 guidelines when meeting with our staff or volunteers by wearing a facial cover over your mouth and nose and maintaining a distance of 6 feet or more.  

Monarch Biology Walk - A one hour walk on many Fridays and Saturdays this fall, beginning on September 11, at 1:30 pm, meeting at the Garrett Family Preserve.  Preregistration required, details here: https://njaudubon.org/event/monarch-biology-3/

Monarch Festival - The Nature Center of Cape May is planning a fun mix of virtual, online programs on Thursday and Friday, September 24 and 25, and activities live and in person at the Center on Saturday, September 26.  Watch for announcement of the details here: https://njaudubon.org/centers/nature-center-of-cape-may/

New Jersey Audubon's Cape May Fall Festival, October 2 - 4, a virtual event that will include a live broadcast of monarch tagging.  Details here: https://njaudubon.org/cape-may-fall-festival/

Field season underway

Sept. 2, 2020

Our field season began yesterday, and we've been getting this year's seasonal crew familiar with the census and other elements of the job.  They'll be conducting the driving census 3 times a day until October 15, then twice a day from October 16 to October 31.  This is the 29th fall for this census, one of the longest running quantitative studies of any migratory insect.  We're seeing a few monarchs around the southern tip of New Jersey, but most aren't showing migratory tendencies.  This isn't a surprise, early September monarchs in Cape May are usually part of the penultimate generation of the year, parents of the ones that will go to Mexico.

Our team has also started tagging monarchs.  With the help of volunteers, our team will probably tag between 2,000 to 4,000 monarchs this fall.  With luck, some will be found in the mountains of Mexico and a some of the places in between, helping us better understand the routes that monarchs take after passing through Cape May.

Here's one of the first monarchs tagged this season.  The tags are small adhesive disks placed on the underside of a monarch's hind wing.  Each tag has a unique code of 4 letters followed by 3 numbers.  The web address mwtag.org is also printed on each tag.  If you ever find a monarch with a tag, try to read the code (digital cameras work well for this, when you can enlarge the photo on your computer) and then go online to that site, mwtag.org, and click on the link: "Report your tag recovery here."  You'll be asked to report the tag code, plus the date and location where you found the monarch.  By reporting this information you'll be contributing to our efforts to better understand details of monarch migration.

Bill Schuhl

 This year we dedicate our work to the memories of three great friends of monarchs from Cape May Point who all passed away since the end of our last field season.  Bill Schuhl, Pecki Witonsky, and Mildred Morgan were all great supporters of our project for many years.  The tagged monarch shown above was tagged in the garden of Pecki, where the new homeowners are maintaining the garden and welcoming our team to continue tagging at the hotspot for monarchs.  With each monarch tagged this year we'll offer silent thanks to these three great friends; we miss them all terribly.

Pecki Witonsky

Mildred Morgan