New Jersey’s Key Role in the Monarch Migration

The Garden State annually hosts swarms of southbound Monarch Butterflies

By: Kendall Miller, Project Coordinator

Monarch butterfly refueling in Cape May as it prepares for fall migration to Mexico. Photo courtesy of Lindsey Brendel.
Monarch butterfly refueling in Cape May as it prepares for fall migration to Mexico. Photo courtesy of Lindsey Brendel.

Monarch has been a conservation buzz-word for the past decade when data revealed that the population had appeared to be on the decline. Then in 2013, the population of wintering monarch butterflies in Mexico reached an all-time low that jolted scientists, environmentalists, and enthusiasts across the nation.

Monarch abundance in wintering grounds is measured as area in hectares. They roost in large colonies in the Transvolcanic Mountains in Mexico. The 2013-2014 overwintering population experienced the lowest recorded area to date, at 0.67 ha. From MonarchWatch.org.
Monarch abundance in wintering grounds is measured as area in hectares. They roost in large colonies in the Transvolcanic Mountains in Mexico. The 2013-2014 overwintering population experienced the lowest recorded area to date, at 0.67 ha. From MonarchWatch.org.

This marvelous and iconic lepidopteran is found throughout the continental United States. Its 3,000 mile long migration is an amazing natural phenomenon. The news of population declines in Mexican wintering sites inflamed concern and incited action. Many groups have since created partnerships, implemented programs, and conducted research to understand more about this widely known yet still mysterious insect.

The location of wintering monarchs was a complete mystery until 1975 when the remote wintering sites were discovered in transvolcanic mountain ranges in Mexico. Much is still to be discovered about the migration pathways even within the United States, and doing so will answer questions which will inform conservation and management of this species which faces multiple threats during every aspect of its expansive journey.

Glider pilots have observed monarch butterflies at an altitude of 1200 meters (Gibo 1981).  Migratory flights at these altitudes can allow insects to disperse against wind directions found at lower altitudes.


But first, a little bit about biology and the annual life cycle

The monarch’s annual lifecycle is a really marvelous and multifaceted journey – it can be thought of as a multigenerational relay race.

From the Xerces Society. Map depicts the known general migration routes of monarch butterflies.
From the Xerces Society. Map depicts the known general migration routes of monarch butterflies.

Monarch butterflies, just like other lepidopterans, metamorphosis from caterpillar to butterfly. The big thing that sets them apart is the migration they make annually. (Although there are many other species of moths and butterflies, and other insects as well that migrate – the monarch is arguably the most well recognized example http://texasento.net/migration.htm).

Temporal cues and an innate determination drive these ambitions fliers to travel as far north as the Canadian border. In the search for milkweed and favorable temperatures – possibly to avoid disease pressures – monarchs fly north to reproduce and recolonize across North America each year.

They leave overwintering grounds in Mexico in early spring. Along their route the monarchs will mate and reproduce. Their lives are lived within a short couple weeks, and their offspring will continue the migration northwards in search of food and milkweed.

When the seasons shift in late summer and early fall, the last generation of monarchs will begin a southbound journey, instinctively traveling to wintering sites in Mexico (there are a few populations that overwinter in California and Florida – but the large majority are thought to return to Mexico). This generation will be responsible for making the longest trek of the migration to wintering grounds. These monarchs enter reproductive diapause – the state where the body will temporarily pause reproduction – until the following spring. These monarchs will spend the winter roosting in trees in Mexico until spring when they will take up the first leg of the relay north.

This last generation from the previous year now makes up the first generation of the present year – and will pass the baton on to their offspring as the cycle starts anew.


The role of the Garden State

So what part does New Jersey play in the grand scheme of this massive population?

The Atlantic coast migration was once characterized as “aberrant”, a fluke of sorts – the result of southbound monarchs being blown off course. Research and monitoring conducted in Cape May and published by Walton and Brower (1996) in The Journal of the Lepidopterist’s Society have supported the hypothesis that a migration along the Atlantic coast is part of the monarch’s normal fall migration.

What does a monarch have in common with a hawk?
Walton and Brower (1996) have proposed the idea that monarch butterflies could display similar flight patterns to that of migrating hawks. Utilizing an elliptical flight path during the fall south-bound migration, the model suggests that these birds take advantage of prevailing winds by first traveling east and then west, thus providing a quicker and more energetically-efficient route. Could monarch do the same?

New Jersey – Southern New Jersey and Cape May in particular – is historically recognized as a concentration area for southbound monarchs during the fall migration to wintering grounds. Hamilton (1885) [expressed his wonder of the] characterized the September 1885 monarch migration at Brigantine, New Jersey as “almost past belief … millions is but feebly expressive … miles of them is no exaggeration.” Reports of trees “more orange than green” is no exaggeration, as monarchs congregate en masse in prime roosting spots to warm and rest.

But why is this important? The monarchs migrating through Cape May seem to be representative of the entire North Eastern population – and therefore it offers the opportunity to collect quantitative data on populations in addition to other annual counts. The fourth of July counts focus on quantitatively monitoring the Northeastern population of monarchs as they arrive in the spring and summer. Therefore this data can be used to analyze population trends.


What part can New Jersey residents play?

Monarchs are traveling across New Jersey May through October. There are plenty of simple ways you can help protect this iconic species.

  • Plant native species of flowering plants – monarchs and other insects (like bees) rely on a healthy diversity of nectar sources. Planting a wildflower garden is a quaint, ecological-friendly way to create habitat, and not to mention, make less work watering and money spent purchasing plants. Check out the Native Plant Society or Jersey Friendly Yards to get started. http://npsnj.org/ http://www.jerseyyards.org/
  • Share this article, talk about environmental issues, and get informed. Show your support and share your concern for the wellbeing of this (and other) species!
  • Rear monarchs. At home or in classrooms, rearing wild monarchs and releasing them is a rewarding and educational way to contribute.
  • Participate in tagging and monitoring projects. Monitoring and tagging projects take place in the summer and fall for New Jersey Monarchs. You can also contribute simply by reporting your sightings on these websites.

LEARN MORE


 

How You Can Help Fill-in Data Gaps

YOUR WILDLIFE SIGHTINGS CAN HELP INFORM NEW JERSEY’S BIOLOGISTS

By Michael Davenport, GIS Program Manager

Compared with most of the states within the United States, New Jersey is relatively small in area. However, it is still too large for biologists within New Jersey’s Endangered and Nongame Species Program (ENSP) to survey every inch of the state for rare species at all times. Therefore, ENSP has created a Rare Wildlife Sighting Report Form with which any bird watcher, hiker, fisherman, and anyone else with knowledge on how to identify New Jersey’s rare wildlife, may submit information on rare species which they may have come across in their travels. This information assists ENSP biologists in monitoring their species’ numbers and whereabouts and may aid in targeting areas for future surveys. Conserve Wildlife Foundation of New Jersey (CWF) staff work very closely with ENSP to encourage the public to submit their observational data and then process the information which gets submitted.

A spotted salamander, photographed during a quiet moment along the road shoulder. © Brett Klaproth
A spotted salamander, photographed during a quiet moment along the road shoulder. © Brett Klaproth

The first step in reporting rare species sightings is to first determine whether the species you observed is a species which is tracked. Tracked species are those listed in New Jersey as endangered, threatened, or special concern. The lists of these species can be found on these ENSP’s websites:  endangered & threatened species and special concern species.

The greatest need for data is for those species which are new to the proposed list of endangered, threatened, or special concern species. Because they did NOT previously have an imperiled status, they have largely been ignored in terms of survey effort and/or data acquisition. At the current time, there is a great need for data regarding observations of the following species:

Reptiles

Amphibians

Butterflies

Once you have determined that you observed a rare species, the next step is to complete a Rare Wildlife Sighting Report Form. You may complete one of these forms if you made the observation yourself – second-hand observations or information whose source was a report, letter, conversation, or other document will not be accepted. Also, one form must be completed per species. Thus, if you observe a heron rookery comprised of great blue herons, tricolor herons, and snowy egrets, then three sighting report forms may be submitted.

Rare Wildlife Sighting Report Forms are available for download and/or printing here. Part of the process of completing the form is to submit a map of the location where the animal was observed. This is critically important for reasons to be discussed later. The preferred map to submit is an aerial image of the area which you have marked with the animal’s location; however, a topographic map is also acceptable. Aerial images may be accessed via Google maps. Topographic maps can be accessed here. In addition to the form and map, it is also extremely helpful if you can submit at least one photograph of the animal in order for an ENSP biologist to verify the identification of the species.

In 2016, the NJ Endangered & Nongame Advisory Committee approved that the rough green snake be added to the state's list of Special Concern species. © Keara R. Giannotti
In 2016, the NJ Endangered & Nongame Advisory Committee approved that the rough green snake be added to the state’s list of Special Concern species. © Keara R. Giannotti

After you mail in your form and map to ENSP, CWF or ENSP staff will enter it into their tracking database at which point it will receive an Observation ID number. You will then receive an e-mail acknowledging receipt of your form and providing you with your Observation ID number in the event you wish to follow-up with additional information or inquire as to whether the biologist has reviewed your form.

The form then goes to a CWF or ENSP biologist who will evaluate it to determine whether it is a valid sighting and whether it should be integrated into the next version of ENSP’s Landscape Project. This is why receiving accurate locational information along with the sighting report form is crucial. The Landscape Project is a Geographic Information Systems (GIS) product whereby critical areas are identified for imperiled species based upon species locations as well as land-use classifications. The resulting maps enable state, county, municipal, and private agencies to identify important habitats and protect them in a variety of ways. This information is even utilized to regulate land-use in the state and attempt to preserve whatever endangered and threatened species habitat remains in New Jersey.

A common misperception many New Jersey nature watchers have is, if they happen to report their rare species sightings to institutions such as Audubon or Cornell (e-bird), that information will make its way to the state’s Endangered and Nongame Species Program. That is not the case. ENSP needs you to submit your data directly to them. So, please, become a Citizen Scientist and assist both CWF and ENSP in tracking New Jersey’s rare species, in the hopes that our work can prevent them from becoming rarer.

If you have collected a large amount of data and submitting it via multiple Sighting Report Forms may be too time consuming, please contact Mike Davenport, CWF’s GIS Program Manager, at Michael.davenport@dep.nj.gov Other options exist for data submittal (Excel spreadsheets for example) so long as all of the required information is included.

CWF’s Online Field Guide Expands

23 WILDLIFE SPECIES ADDED TO CWF’S ONLINE FIELD GUIDE

By Michael Davenport, GIS Program Manager

Conserve Wildlife Foundation of NJ’s online field guide, a one-of-a-kind free reference focused on New Jersey’s wildlife, has recently expanded to include 23 additional species. As a result of recent status reviews by the state’s Endangered and Nongame Species Program for reptiles, amphibians, and butterflies, additional species within the state will be receiving an imperiled status of either Endangered, Threatened, or Special Concern. Six reptile species are being added as well as four amphibians and thirteen butterfly species.

Baltimore_Checkerspot_1
The Baltimore checkerspot, a species recently added to CWF’s on-line field guide. Photo courtesy of Eric C. Reuter.

Later this week, two additional blog entries will be posted regarding the status review process and the new listings. The posts will be: “Species Status Review process” (WEDNESDAY); and “How you can help fill-in data gaps” (FRIDAY).

The list of “new” species is below and each species name links to its field guide entry on our website:

REPTILES

AMPHIBIANS

BUTTERFLIES

Six Beautiful Butterflies that Call New Jersey Home

A Closer Look at Six At-Risk Butterflies Found in the Garden State

By: Kathleen Wadiak, Wildlife Conservation Intern

New Jersey is home to a number of butterfly species as diverse as the different habitats throughout the state. Whether you live by the shore, a forest, or open fields, you can find a few of these species during their flight period, which usually takes place during the summer months. While it is no secret that the state can be home to well-known butterflies such as the Monarch, here are six butterflies that also call New Jersey home.

 

Baltimore Checkerspot

Baltimore Checkerspot
The best time to see a Baltimore checkerspot is early June to early August. This medium-sized butterfly a wingspan of about 1 ½ to 2 ½ inches. They are black with an orange border and speckled with white and orange markings. Checkerspots can be found in the northern half of the state in wet, stream-fed meadows consisting of mostly tall herbaceous growth. White turtlehead is a necessity in its habitat as it is the food source for developing caterpillars. The checkerspot’s unique environmental needs make it particularly vulnerable to habitat destruction and fragmentation.

 

Compton Tortoiseshell

Compton Tortoiseshell
Compton tortoiseshell butterflies have a flight period of March to November, during which they can be found in northeastern New Jersey in mixed and deciduous forests. In the forests, they make use of shelters created by tree cavities and nearby building eaves. Compton tortoiseshells can be identified by their orange-brown, black spotted wings with both the forewings and hindwings having a single white spot on the leading edges. The undersides of the wings are mottled gray brown with a small white “V.” With a wingspan of 2 ½ to 3 inches, they are a relatively large butterfly. The majority of this butterfly’s diet consists of rotting fruit and sap. Populations often fluctuate dramatically from year to year depending on habitat quality and climate factors.

 

Eyed Brown

Eyed Brown
Sightings of eyed browns occur from early June to late July in northeastern New Jersey, with most reports coming from Sussex County. They occupy open wetlands including sedge meadows, cattail marshes, and tall grasses alongside slow-moving streams where there are sedges for its caterpillars to feed on. Adults feed on rotting fruit, sap, and bird droppings. The eyed brown gets its name from its wings. About 1 ½ to 2 ½ inches across, they are pale brown, with the color darkening toward the body. On both sets of wings, there are black “eye” spots that are larger on the hindwing. The undersides of the wings are also pale brown, but have jagged lines running across them.

 

 

 

 

Hickory Hairstreak

Hickory HairstreakHickory hairstreaks can be seen from mid-June to early August in the northern half of the state. Their habitat consists of deciduous and second growth forests and adjacent fields. The forests in its habitat almost always consist of hickory trees, as they are the primary food plant of its caterpillars. Adult butterflies feed on the nectar of a variety of flowering plants including common milkweed, New Jersey tea, and white sweet clover. The hickory hairstreak is a relatively small butterfly with a wingspan of approximately 1 to 1 ½ inches. It is rarely seen with its wings open and is identified by the dark postmedian “dashes” and white outline on the underside of its grayish brown wings. On the hindwing, there is a pale blue patch that extends inward further than the adjacent orange and black spots. There is one tail on each hindwing.

 

Northern Oak Hairstreak

Northern Oak Hairstreak
The flight period of the northern oak hairstreak lasts from mid-June to mid-July, during which they can be spotted in southern New Jersey oak forests and adjacent openings. Caterpillars of the northern oak hairstreak feed on the leaves of various oak species while adults feed on the nectar of flowers including New Jersey tea, milkweed, meadowsweet, and maleberry. The northern oak hairstreak is a small butterfly with a wingspan of approximately 7/8 to 1 ½ inches. The underside of the forewing and hindwing is gray-brown and has black and white, narrow postmedian bands, which form an “M” on the hindwing. There is a blue tail spot on the hindwing that is capped by orange and black. Each hindwing has one tail.

 

Rare Skipper

Rare Skipper
The rare skipper can be found along the southern coastal regions of New Jersey from May to September. Instances of rare skipper populations occur on a very local basis, and very little is known about the species. Their habitat consists of fresh and brackish wetlands along tidal rivers and marshes as well as abandoned rice paddies further inland. Caterpillar host plants include tall cordgrass in northern and coastal habitats and giant cutgrass in some southern wetland areas and abandon rice paddies. Adult rare skippers feed on nectar from wetland flowers such as swamp milkweed and pickerelweed. Rare skippers can be identified by their bright yellow-orange wings with a broad, dark border around the upper-side of the forewing and hindwing.

 

Kathleen Wadiak is a Wildlife Conservation Intern with the Conserve Wildlife Foundation of New Jersey.