Impact of White-Tailed Deer on Arlington’s Forests

by Leslie Cameron and Bill Browning

In mid-November, ARMN members Bill Browning, Jeff Elder, Steve Young, and Leslie Cameron met with Arlington Parks and Recreation Conservation and Interpretation Manager Rachael Tolman to evaluate a deer “exclosure” in Gulf Branch Park. 

Photo of ARMN volunteers standing in front of a deer exclosure
L-R: Rachael Tolman, Steve Young, Bill Browning, Jeff Elder at damaged Gulf Branch deer exclosure. Photo by Leslie Cameron.

The deer exclosure was built in 2017 as part of an Eagle Scout project for a local Boy Scout troop to protect the vegetation inside from deer browse. As the white-tailed deer (Odocoileus virginianus) population in Arlington has grown, their impact on Arlington’s forests has grown too. Deer exclosures are one strategy for protecting habitat from deer browse and can also play a role in collecting data on the impact of deer in our forests. They can also potentially play a big role in educating people, who can compare protected and unprotected areas as they walk by. In the 4 years since it was constructed, the deer exclosure in Gulf Branch has fallen into disrepair.

Photo showing a damaged deer exclosure.  The fencing is crumpled and has pulled off the post.
Damaged deer exclosure at Gulf Branch Park. Photo by Bill Browning.

The group discussed repairing or rebuilding the exclosure (exclosures need to be 8-10 feet high to effectively exclude deer) and reducing the size to make it easier to maintain. To collect data on the impact of deer, a fenced exclosure (the “variable”) is paired with a same-size nearby unfenced reference plot (the “control”). The diversity of species and quantity of vegetation in both plots is documented over time. Signage can inform the public about the project, as well as discourage residents from disturbing it. 

Impact of deer on a healthy forest

Deer are Virginia’s largest herbivore. An adult eats 5-7 pounds of vegetation a day, or a ton each year. If there are more deer than the land can support, deer browse begins to degrade the understory in a forest. The forest understory—forest floor, herbaceous plants, shrubs, seedlings, and young trees—supports native ground-nesting birds, insects, reptiles, and amphibians. Deer browse limits the food and cover for these species, and they decline. The understory also includes the young trees that form the forests of the future. A forest without its understory cannot regenerate, which means that there will be no mature trees in the future. Because deer prefer native plants, deer browse disturbs the diversity of plants, and allows invasive plants to multiply in their place. 

Photo of the understory at Lacey Woods Park
Lacey Woods Park in Arlington has not been heavily deer browsed and has a healthy understory. Images 3 and 4 were taken on the same day in November 2021. Photo by Steve Young.
Photo of the understory at Long Branch Nature Center
Long Branch Nature Center Park has been heavily deer browsed. Without a healthy understory, forests cannot regenerate. Images 3 and 4 were taken on the same day in November 2021. Photo by Steve Young.

Male deer also rub antlers on trees, which can damage them. For more background on the effects of deer on our forests, see the May 2020 ARMN blog article, “White-tailed deer and Forest Health in Northern Virginia.”  

Deer population over time   

By the 1930s, deer had almost disappeared from Virginia and had declined in many eastern states. States implemented regulations to protect deer and their habitat, and the population began to rebound.  Effective predators of deer (like the gray wolf and eastern cougar) were extirpated from Virginia, and development and fragmentation have increased edge habitat, which deer prefer. These changes have contributed to a rapid increase in the population of deer. 

Graph of deer population of Virginia from 1600 to present.  Present population is between 1 million and 1.25 million.
From p. 11, Fig 2 of: “Virginia Deer Management Plan 2015-2024.”

Assessing Arlington’s deer population and next steps

In response to concerns about the impact of deer in Arlington’s forests and other natural areas, Arlington County hired an independent contractor to conduct a drone survey of the population in spring 2021. Some Federal property owners (National Park Service, Pentagon, Arlington National Cemetery, Reagan National Airport) did not grant permission for the aerial drones so these areas were excluded. Further, the contractor was unable to obtain a permit to fly the drones at night when the heat signatures are easier to detect. The survey counted a minimum of 290 deer in Arlington that were concentrated in wooded and natural areas. Four of the survey sections had deer counts at levels which most experts agree is too high for regeneration of native plants. All of Arlington’s seven Natural Resources Conservation Areas had too many deer. The contractor recommended aggressive deer management, particularly in those areas. 

Bar chart of deer population in Arlington neighborhoods.
From p. ii of: “White-tailed deer (Odocoileus virginianus) Population Density Survey using sUAS Infrared: Arlington County, Virginia – Spring 2021” that shows the approximate numbers of deer in Arlington neighborhoods.

Arlington is in the process of hiring a second consultant to determine if a deer management strategy is needed and if so, to develop an implementation plan. Please see the County’s website for its current plan.

One management strategy some jurisdictions have considered is immunocontraceptive vaccines such as porcine zona pellucida (PZP) or GonaCon. In practice, this strategy has challenges with open herds. Annual injections may be needed to produce infertility. These vaccines are injected by hand into captured deer or hypodermic darts are fired remotely. Deer are susceptible to capture myopathy muscle damage that results from the extreme stress of being repeatedly captured. Darts delivered remotely can miss the target or fall out before delivering the dose. Despite many attempts nationwide, there are few reported instances where these medical intervention strategies have proven even marginally effective. Moreover, the Virginia Department of Wildlife Resources does not approve of these techniques for managing the size of deer herds.

Another strategy is managed hunting, which can take several forms, depending on location. This method usually involves professional sharpshooters or volunteers with rifles or archery tackle. Managed hunts can be conducted safely in restricted or urban areas, and done properly, result in very low rates of nonlethal wounding for deer. As noted in the 2020 ARMN blog piece cited above, neighboring jurisdictions have taken steps to manage their deer populations. Fairfax County has had a deer management program in place since 1998. Montgomery County established a deer management program in 1996. Both counties use all three hunting methods. The National Park Service established a deer management plant in 2012; the NPS primarily uses professional sharpshooters who hunt at night in collaboration with a variety of police authorities. All three jurisdictions have had no safety incidents since their programs’ inceptions.

Where they are highly concentrated, deer are damaging forests and degrading habitat in Arlington, at the expense of the other species that occupy the ecosystem, including mammals, birds, reptiles, and insects. Without natural large predators (wolves or mountain lions,), the deer population is out of balance. It is important to take steps to restore this balance to protect the future of Arlington forests and all their inhabitants.

Actions members of the public can take 

Learning about the impact of deer on forests and other natural areas is critical. Anyone can assist in education efforts:

  • Share this blog piece with friends and neighbors in community newsletters and on “Next Door” or other community social media.
  • Is your neighborhood community group interested in a deer education presentation? If so, send that information to ARMN via “Contact Us” on armn.org.  
  • Ask about nature walks to bring attention to the impact of deer in natural areas via ARMN’s “Contact Us” feature.
  • Participate in Arlington programs that are approved to rebuild and maintain deer exclosures and gather data on the impact of deer on natural areas. 
  • Avoid feeding deer or encouraging them to approach. You may also protect your landscape with a deer exclosure and other strategies. For more details, see: Virginia Cooperative Extension publication, “Deer: A Garden Pest.”

For more information 

The following resources have more information about the impact of deer in natural areas and about Arlington’s process for assessing the problem and determining next steps.

ARMN resources:

Deer Management

Arlington County Deer Survey and Next Steps:

Click to access arlington-county-deer-survey-and-next-steps.pdf

ARMN Ozone Garden Work Continues at Walter Reed Community Center

by Barbara Hoffheins, Todd Minners, Terri McPalmer, and Jon Bell

In 2020, Arlington Regional Master Naturalist (ARMN) volunteers initiated the Ozone Garden with the cooperation and support of Arlington County Parks at Walter Reed Community Center (WRCC) located at 2909 16th St S, Arlington, VA 22204. (The beginnings of this project were reported in an earlier blog piece, “The Ozone Bio-indicator Garden Project: A Cooperative Effort Between ARMN, Arlington County, NASA, and Harvard.”) 

The garden is part of the Ozone Bioindicator Garden Network, which is coordinated by the Harvard University and Smithsonian Institution Center for Astrophysics (Smithsonian Astro Observatory), and affiliated with the National Center for Atmospheric Research (sponsored by the National Science Foundation), and the National Aeronautics and Space Administration (NASA). NASA’s TEMPO (Tropospheric Emissions: Monitoring Pollution) mission is to measure air pollutants at high precision across North America with a specially designed instrument scheduled to launch on a satellite in 2022.  

The observations of ozone effects on plants in the ozone gardens add to the understanding of ground-based ozone seasonal patterns, distribution, and intensity. Ozone is formed by the interaction of sunlight with carbon monoxide from burning fossil fuels, nitrous oxides, and volatile organic compounds (VOCs). Elevated ozone levels can seriously damage crops and forests and cause respiratory damage or distress in humans and animals. See: USDA Agricultural Research Service report. These and other reasons are why NASA is interested in monitoring and tracking ozone globally. 

Ozone enters the leaves from the underside through the stomata and interferes with the photosynthetic process. Ozone damage is typically observed as brown stippling (spots), on the tops of mature leaves, in between and not crossing the veins, and for many plants, not visible on the underside of the leaf. The damage starts with a few spots and can increase to cover and eventually kill the leaf. Insect damage, such as chewing or cutting, and disease effects are visible on both the tops and bottoms of leaves but can be mistaken for ozone damage.

Photo of a leaf showing yellowing and spots
Sensitive bean damage from ozone (spots) and insects (holes) observed August 13, 2021. Photo by Barbara Hoffheins.

Ozone damage to leaves of sensitive plants can be observed when the ozone level is sufficiently high over a long enough period. This could be a very high level of ozone for as few as two hours or a moderate level for many hours or days. The bean plants in ARMN’s Ozone Garden started showing signs of ozone damage in late summer. To roughly correlate with the visual observations, data was used from the Arlington County air pollution monitor located at Aurora Hills Visitor Center that measures and reports nitrogen oxides, carbon monoxide, and ozone levels on an hourly basis. During the 2021 growing season, there were very few days when the Aurora Hills monitor reported ozone at sustained elevated levels and most of the days were in late July, early August. 

ARMN’s Ozone Garden is located on the west side of the WRCC building near a children’s playground. In the spring of 2021, ARMN volunteers constructed three raised beds and planted the following provided by the Smithsonian Astro Observatory:

  • Sensitive and tolerant varieties of snap beans (Phaseolus vulgaris): tolerant is var. R-123, sensitive is var S-156. 
  • Sensitive and tolerant varieties of tobacco (Nicotiana tabacum L.): var. BEL B is tolerant, var. BEL W3 is sensitive.
  • Sensitive potato (Solanum tuberosum): var. La Chipper.
  • Sensitive milkweed (Asclepias syriaca).  
Photo of a garden planted in raised beds
Garden on July 27th at the peak of growing season. Photo by Barbara Hoffheins.

ARMN prepared informational signs in English and Spanish about the garden purpose and ozone effects to inform passersby. The volunteers monitored the garden throughout the season to water, weed, and report observations of the plant leaves. Sometimes visitors to WRCC stopped by to chat with volunteers.

ARMN volunteers learned a lot this season. Although the volunteers collectively have a variety of relevant skills and expertise, monitoring for ozone damage and distinguishing ozone damage from other garden problems were new activities for all.  Other issues that needed to be address were insufficient water drainage early in the season, a soil test that indicated excessive alkalinity, and plant leaves that exhibited insect and disease damage. The team also installed rabbit protection for the potato plant after discovering bitten off stems and leaves. The volunteers consulted several sources, including experts from the Virginia Cooperative Extension, the Ozone Bioindicator Garden Network, online scientific publications, the U.S. Environmental Protection Agency (EPA), the U.S. Department of Agriculture (USDA), and NASA brochures. 

Recently, the team added some manure where the tobacco had grown, turned over the beds, and planted coneflower and milkweed seeds that need winter weather to trigger germination in the spring in pots that are sunk in the ground. They also tightened up corners of the raised beds that had moved a bit during the summer.

Photo of volunteers standing on a path next to the garden
Winter prep on October 22, 2021. Photo by Todd Minners.

The ARMN Ozone Garden Team has these goals for the 2022 growing season:

  1. Use the garden to illustrate visually the impacts of ozone pollution on plants. 
  2. Add signs with more detailed photos of each type of plant and instructions for how to find ozone damage and include a QR code on the signs to connect to online educational links.
  3. Enumerate actions that anyone can take to reduce ozone levels.
  4. Develop and conduct outreach programs at the garden to educate all ages about air pollution in Arlington and the negative impacts on agriculture and human health.
  5. Collect data on ozone damage present in the garden and report findings to the National Center for Atmospheric Research.
  6. Monitor and maintain soil quality for health and consistency across all three garden beds.

The ARMN Ozone Garden team welcomes visitors to the beds at Walter Reed Community Center to see where the project is taking place. As noted above, the beds are located in front of the building on the west side.

Habitat Restoration at the Fairlington United Methodist Church

Text and images by Leslie Cameron, unless otherwise noted.

On a recent sunny workday in October, volunteers worked to remove invasive plants and plant native shrubs in a habitat restoration area adjacent to the Fairlington United Methodist Church (FUMC), at 3900 King Street in Alexandria.

Photo of an ARMN volunteer posing next to a shrub
FUMC Habitat Coordinator and Extension Master Gardener Anne Wilson, with a Black haw viburnum (Vibernum prunifolium) about to be planted.

In 2018, FUMC designated the half acre of wooded area and lawn near the church parking lot at Van Dorn Street and Menokin Drive as a native habitat restoration area. This parcel of land had been untended for many years, and heavy rains spilled extensive water down the Van Dorn Street hill, creating significant erosion. An initial focus was stormwater management. But FUMC’s long term vision is “to restore and sustain a 1/2-acre habitat of native trees, shrubs, and plants so that the community in the urban area where it is located has access to a place of spiritual rest and renewal, and opportunities for education inspired by the intricacies of the ecosystem.” Extension Master Gardener Anne Wilson and Arlington Regional Master Naturalist Clint Stretch have been the coordinators of the habitat restoration area since its inception. In the first year, paths were created and extensive populations of invasive plants like porcelain-berry (Ampelopsis brevipedunculata), autumn olive (Elaeagnus umbellate), and others were removed. A circle of “stump seats” was added in the second year, inviting not only church members but neighbors from the community to visit. Visitors included children from the Fairlington Presbyterian Preschool across the street, who use the circle for their story time. FUMC welcomes everyone to enjoy the habitat, and many residents in the surrounding communities visit and rest in this space. 

Also, many church and community volunteers continue efforts to restore this area, including ARMN members Carol Weldon, Doug Brown, and Leslie Cameron. While ARMN habitat restoration work is focused on public lands and parks, ecologically significant private property, where the habitat improvements and educational value to the broader community are substantial, may receive special ARMN Board approval, as is the case with the FUMC work.

Grants from the Audubon Society of Northern Virginia and Northern Virginia Soil and Water Conservation District, working with the City of Alexandria, have funded the installation of native plants, including water-retaining plants to help manage stormwater runoff from the parking lot. 

Photo of a Sweetbay magnolia shrub.
Sweetbay magnolia (Magnolia virginiana) planted near the parking lot to help manage stormwater runoff.

In addition, a recent grant from Virginia Department of Forestry’s Virginia Trees for Clean Water Grant Program is funding the planting of native trees to improve water quality, increase the tree canopy, and provide additional wildlife support. On a recent October workday, volunteers planted five black chokeberry (Aronia melanocarpa) and three Black haw viburnum (Viburnum prunifolium) shrubs. Other practices include keeping dead trees standing as “snags” (trees left in place that decompose naturally) and maintaining brush and log piles to support insects, birds, and other wildlife. 

To promote native plants, the church has installed signage explaining the project and is building a demonstration native wildflower rock garden on a bank above the Van Dorn Street sidewalk, including wild geranium (Geranium maculatum), columbine (Aquilegia canadensis), white wood aster (Eurybia divaricata), and goldenrod (Solidago sp.), plus nine redbuds (Cercis canadensis).

Work this year will continue till about mid-November, and Anne and Clint anticipate starting workdays up again in the Spring. Volunteers continue to be needed to pull invasive species and maintain the restored areas. In early spring, FUMC anticipates transplanting numerous small trees to more optimal spaces within the habitat. Anyone interested in joining workdays on regular Tuesday morning events or participating at a different day and time should email Anne Wilson at wilsanne@gmail.com to be added to a workday sign up list.

On-going LDS Volunteering Having a Huge Impact in Five Arlington Parks

By Tina Dudley 

Since October 2020, Cindy Lund has been assigning young men and women from The Church of Jesus Christ of Latter-day Saints (LDS) to work with ARMN Park Stewards for on-going, weekly volunteer service. Master Naturalist Glenn Tobin first met the LDS missionaries and Cindy, an LDS coordinator, through Trudy Roth of National Park Service, who manages volunteers for the George Washington Memorial Parkway. After he worked with them for a day or two, Glenn introduced Cindy to ARMN Vice President, Phillip Klingelhofer, who established the ongoing partnership. 

Currently, LDS volunteers are working regularly in five area parks—Brandymore Castle Park, Tuckahoe Park, Potomac Overview Regional Park, Jamestown Park, and Sharp Park. 

All of the Stewards are immensely grateful for these hardworking, dedicated, and fun-spirited volunteers, as well as Cindy’s efforts. Without Cindy, none of the parks would have benefitted from these amazing volunteers. Gary Shinners, one of the Park Stewards, describes her as incredibly responsive and a joy to work with—she does a great job of coordinating. 

Many of the volunteers have worked tirelessly to remove invasive plants. These plants aggressively consume limited space and resources, and don’t contribute to the energy cycle. It takes millions of years for native plants and insects to co-evolve, so when foreign plants are planted or spread unintentionally, most insects are not able to eat them. This reduces the population of insects that primary predators, like birds, reptiles, and mammals, have to eat, thus reducing biodiversity. However, when these invasives are removed, it makes space for productive native plants to thrive, and creates food and shelter for native animal species. Below are a couple of the many wildlife beneficiaries of this labor of love:

Jo Allen, Park Steward of Brandymore Castle Park, describes the “sisters” (the female LDS volunteers) as “incredibly helpful.” They first started in January 2021 and have come every Thursday and have worked hard to remove porcelain berry (Ampelopsis brevipedunculata) and English ivy (Hedera helix) from the park. In the photo below, Sister Cella is battling with a gnarly root to prevent the porcelain berry from invading a newly planted bed of native buttonbush (Cephalanthus occidentalis), milkweed (Asclepias spp.), blue mistflower (Conoclinium coelestinum) and little bluestem (Schizachyrium scoparium).

Photo of a volunteer removing invasive plants
Photo by Jo Allen.

As she works with the volunteers, Jo weaves in lessons about ecology and botany. The volunteers are enthusiastic and friendly when speaking with members of the public who inquire about the project. 

One volunteer, Sister Cummings, expressed her gratitude for the opportunity: “It was a pleasure serving, I am grateful for the experience, I learned a lot from Jo. I would recommend [that] others serve at parks and get to know the area. It’s a beautiful planet, we should be grateful for it. We show our gratitude by learning about it so we can take care of it.” 

Mary McLean has been a Park Steward at Tuckahoe Park for over 15 years, and she once taught at the elementary school beside the park and often walked her dog at Tuckahoe. Mary’s volunteers from LDS started in February and they have been coming every Tuesday. The women are highly motivated to pick up trash and remove invasives such as English ivy, porcelain berry, and Japanese stiltgrass (Microstegium vimineum).

Photo of volunteers holding a sign that says "volunteers at work" next to a bag of removed invasive plants.
Tuckahoe Park LDS volunteers with their haul for the day. Photo by Mary McLean.

Mary also enjoys teaching the volunteers about the park and the plants within it—both native and invasive. Stiltgrass, native to much of Asia, was introduced as a packaging material for fragile items like ceramics. Mary explained Tuckahoe Park’s interesting geology. It is a bowl-shaped park that used to have a stream but after the stream was buried, there was a shift. With less moisture in the ground, the park unfortunately lost some mature oaks. But this opened up the canopy for the return of a lot of young oak trees and other native plants such as the Virginia jumpseed (Persicaria virginiana). 

At Potomac Overlook Regional Park, Park Steward Gary Shinner’s volunteers have been building garden boxes, erecting bird boxes, fixing fencing, and doing trail maintenance, and pulling invasives. His group of male LDS volunteers (known as “elders”) have come every Friday since March. Gary shared how lucky he is to have their help, saying “If I didn’t have them, I wouldn’t have been able to do any of the projects I have done this year. I consider myself incredibly fortunate.”  

Photo of volunteers standing behind a fence
Potomac Overlook Regional Park LDS volunteers ready for another day of hard work. Photo by Gary Shinners.

About once a month, Gary leads the elders on a hike around the park and teaches them about ecology. They are now very skilled in plant identification and can proudly differentiate porcelain berry from a native grape vine (Vitis spp.). A history-buff, Gary has enjoyed teaching his volunteers about the indigenous people who once lived on the land and even led the group to find rock shavings that were created in the process of carving arrowheads.

Gary also brought the volunteers to another small park, Jamestown Park, which is adjacent to Jamestown Elementary School. The volunteers have removed invasives from a slightly sloped site where the school has agreed to build a rain garden. This incredible before and after photo is a great example of the profound impact LDS volunteers have had in parks across Arlington! 

Photo showing the park before invasive removal and the cleared area after invasive removal
Photo by Gary Shinners.

The area shown here will soon be a native wildflower meadow and rain garden, which never could have happened if the elders had not first removed the non-native invasive plants from the area.

In the process, the elders extracted a long 25-foot porcelain berry vine. It was so long the elders were able to play jump rope with it!

Gary explained that this video beautifully captured the positive attitude and fun-loving nature of his group of volunteers, who worked very hard on whatever they were asked to do but also had fun along the way. 

Colt Gregory has also worked with LDS volunteers in Sharp and Tuckahoe Parks. He described the experience as such: “We learned from each other as we cleared mounds of ivy from Tuckahoe and thick vines and underbrush from Sharp. The group learned to identify and remove the bush honeysuckle (some the size of small trees), wineberry [Rubus phoenicolasius], porcelain berry, and how to avoid (mostly) poison ivy. I learned about the outdoors in the South and West and talked to my groups about the importance of stewardship of the land. It was a different mission from the one they expected but all took to it with strength, perseverance, and good humor. Eventually we had a name—Invasive Assassins—and we wore our t-shirts proudly.” 

Photo of volunteers clearing the invasive underbrush in the park
Elders clearing the underbrush at Sharp Park. Photo by Colt Gregory.

Another group of volunteers worked with Glenn Tobin, winner of Arlington County’s Bill Thomas Park Volunteer Award for 2020. Most of the volunteer effort was along the Potomac Heritage Trail in the George Washington Memorial Parkway near Windy Run, just alongside the Potomac River. From Oct. 1, 2020, to Sept. 30, 2021, Glenn led 28 events with the missionaries and they contributed about 450 hours in total. They removed a lot of kudzu (Persicaria perfoliata), English ivy, and “a lot of just about every other invasive known to human-kind.” Glenn described their incredible impact by saying, “Their work basically added another year of activity to what would have otherwise happened, so we are one year ahead of what we would have been otherwise.”

Photo of a volunteer dragging a large mass of english ivy
An elder dragging a bundle of English ivy the size of a semi-trailer. Photo by Glenn Tobin.

Glenn has been an ARMN member since 2016 and a Trail Maintainer with the Potomac Appalachian Trail Club (PATC) since 2015. For years, he removed invasive plants at Windy Run Park and the adjacent Potomac River waterfront in the George Washington Memorial Parkway. Because of his work alone and with other volunteers, significant natural areas are recovering and becoming more beautiful and biodiverse. In 2020, Glenn raised money and worked with the PATC and the National Park Service (NPS) to rebuild the stone stairway that connects the Windy Run Park trail to the Potomac Heritage Trail along the Potomac River, improving access for many people. Then, inspired by the reemergence of diverse native flora at Windy Run and along the Potomac, Glenn began working with experts in ecology, botany, and natural resources to create the website, Natural Ecological Communities of Northern Virginia, which provides information about the local natural plant communities to help people make better plant selections for ecological restoration purposes in Northern Virginia, Washington D.C., and close-in Maryland. (See: related ARMN blog piece.)


On behalf of ARMN, I want to applaud the continued hard work of LDS volunteers and the Park Stewards all across the Arlington Region. Readers who would like to get involved in their own local park are encouraged to contact us to be connected with a Park Steward. It is a great opportunity for team building and service for your family, workplace, or place of faith—and who knows what wildlife you may find in the process!

ARMN at the Arlington County Fair!

By Devin Reese

Photo of an Arlington County resident holding pamphlets from the ARMN table.
Arlington County resident “Ace” visiting the ARMN table. Photo by Devin Reese.

 During the weekend of Aug. 21-22, ARMN volunteers staffed an information table at the Arlington County Fair. Adjacent to the Virginia Cooperative Extension (VCE) and 4-H Youth Development tables, we were in a great spot for collaboration and outreach with the Fair’s visitors. 

The ARMN table offered a variety of visual materials, including an ARMN poster on Stewardship and Citizen Science, enticing people to plant natives and get involved in bioblitzes and other wildlife inventories. The “Being a Good Neighbor” brochure explained how to adopt practices on your property, such as providing habitat for wildlife to enhance the ecological well-being of neighboring parks. A “Deer Management” handout alerted people to the negative environmental consequences of unmanaged deer populations. Audubon materials were also on display, including “Plants for Birds” and “Making Your Windows Safer for Birds.” The PlantNovaNatives brochure on “Native Perennials for Your Garden” included free seed packets for several native pollinator favorites: Cardinal flower, Milkweed, and New England aster. And a suggested donation of five dollars had visitors taking a copy of the thick, colorful booklet on “Native Plants for Northern Virginia.” 

A steady stream of visitors trickled by the table. Some steered right over at the sight of the wildlife materials, while others were lured with a friendly “Hello.” The variety of interests and intentions visitors brought underscored the broad appeal of connecting with our natural environment. 

Arlington resident, “Ace,” was excited to discuss the diversity of plants she was growing in her apartment balcony garden, which included an eastern redbud (Cercis canadensis) she had been given by Arlington County’s Adopt-a-Tree program. A young couple from Southwest D.C. has no land around their apartment building but dreamed of a future garden. Inspired by the Fair’s agricultural competition, the woman hoped one day to grow a prizewinning gourd, while her husband fantasized about putting Cardinal flowers in his future flower garden. Recognizing the lack of planting opportunities for apartment dwellers, a building superintendent for an 8-unit apartment complex discussed what tenants could plant on their balconies.

Also from Arlington, David came over to ask about how and when to cut back his roses. The Arlington Master Gardener at the adjacent VCE table was able to give him some guidance about pruning them in late fall or early winter after they’ve bloomed. 

Photo of an ARMN volunteer speaking with a visitor with the ARMN booth visible in the background.
Visitor David discussing roses with Master Gardener Joan McIntyre. Photo by Devin Reese.

Two passersby noticed the American goldfinch (Spinus tristis) on the Audubon at Home brochure, and it sparked a conversation about which plants could attract goldfinches to yards. An elementary school girl proudly described the garden she was cultivating by herself and that it was so chock full of plants that she couldn’t add any more.

Some Westover neighborhood residents lamented that they had planted butterfly bushes (Buddleia davidii) but couldn’t seem to keep them alive. This is just as well; Butterfly bush is an invasive, nonnative plant in this region. They took seed packets of the New England aster (Aster novae-angliae) to make a fresh attempt at attracting butterflies with a native plant. Another couple newly-moved to the area were curious about where to buy native plants. Master Naturalist Colt Gregory directed them to Earth Sangha, Nature by Design and the Nova Natives sales at Green Spring Gardens

Photo of an ARMN volunteer holding up an example pamphlet available at the ARMN booth.
Master Naturalist Colt Gregory shares brochures and wisdom with ARMN booth visitors. Photo by Kirsten Conrad.

Editor’s note: see the related piece “Fall 2021 Native Plant Sales” on the ARMN homepage sidebar that lists a number of local native plant sales in September and October. 

There were also visitors stopping to discuss specific environmental concerns. A Maywood neighborhood resident had noticed the die-off of white oaks (Quercus alba). We talked about how oaks in this region are suffering Sudden Oak Death because of a fungal pathogen that infects the living tissue under the bark. (Editor note: Sudden oak death has not yet been detected in the area.) He had also noticed that many trees were colliding with power and phone lines and advocated for moving utility lines underground to make more canopy space for trees. Another resident shared that, while she loved using her compost as rich soil, the unfortunate outcome was lots of stray seeds germinating and shading out the butterfly flower she had intended to grow. 

Photo of two visitors and an ARMN voln
Master Naturalist Marj Signer addresses visitors’ questions. Photo by Kirsten Conrad.

Overall, the combined attraction of the side-by-side tables and lots of visual material related to wildlife and natural resources management seemed like an effective way to ignite conversations at the Arlington County Fair. We even got a visit from the former County Board Chair, the Honorable J. Walter Tejeda! The Fair highlighted just a few of the benefits that ARMN and VCE provide. Plan to contact us with questions you may have about and ways you can support our local natural environment while enjoying its beauty. 

Battling Invasives at Glencarlyn Park

Text and Photos by Devin Reese, except as noted.

Arlington Regional Master Naturalists have a vendetta against invasive plants because of the damage these invaders do to ecosystems. Invasive plants outcompete native plants, disrupting age-old relationships with insect pollinators and typically reducing the biodiversity of an area.

Go on an invasives removal field trip with an ARMN volunteer and you’re guaranteed to witness moments of reckoning between human and plant. Those moments, kicked off by exclamations of dismay such as “Oh no, that’s kudzu!” often involve clipping, lopping, grappling, tugging, hurling, bagging, and otherwise taking invasive plants to the mat. 

If you want to join in the excitement of plant wrestling, there’re plenty of regular outings in Northern Virginia. One of those is the invasives removal program at the Long Branch Nature Center’s Glencarlyn Park in Arlington, monthly on Sunday afternoons. Wear long pants and bring your gloves, clippers, and enthusiasm for helping native plants. The site offers extra gloves and tools if you arrive empty-handed.

One of the people you’re bound to interact with is Long Branch Environmental Steward Steve Young, who is a font of information about the native and introduced flora. He’ll lead you through recognizing and removing invasive plants, while sharing plant-related lore. 

Photo of volunteer holding up a garlic mustard plant
Steve Young shows seed heads on garlic mustard (Alliaria petiolata).

You’ll likely remove garlic mustard (Alliaria petiolata), a common invasive that has cropped up all over the NOVA region. Crush its leaves for a whiff of garlic, which explains its introduction from Europe as a food plant. Despite its tastiness to humans, garlic mustard is not palatable to native wildlife. Because it can self-pollinate or cross pollinate, produce lots of seeds, and grow in shade or sun, garlic mustard spreads fast. Steve will show you how to tug it gently, roots and all, out of the ground, and bag it to keep the seeds off the soil. 

Another plant Steve will point you to is the mile-a-minute vine (Persicaria perfoliata) that was introduced from Asia and first got a foothold in the U.S. at a plant nursery in Pennsylvania, from where it spread. Its delicate stems and leaves bely its hazard as an introduced species. Its other common named, “devil’s tear thumb,” comes from miniscule, curved barbs on the stems and triangular leaves. Using its barbs to cling to other vegetation, mile-a-minute vine grows up to six inches a day, spreading laterally and horizontally. Feel the sticky barbs as you extract the vine from its hold on native vegetation.

Photo of a volunteer pulling a vine
Volunteer Erin removes mile-a-minute vines (Persicaria perfoliata).

Expect Steve to show you some introduced plants that are problematic but cannot be eradicated by pulling them. For example, while small areas of Japanese stiltgrass (Microstegium vimineum) may be removed by hand, it can quickly grow into dense stands to create short, vertical groundcover. Creeping Charlie (Glechoma hederacea) makes ivy-like blankets, but pulling it out will be futile, says Steve. When he first started working at Long Branch about 25 years ago, he says he was “totally anti-chemical and didn’t believe in ever using herbicides.” But he soon realized that “if you don’t use herbicides, you’re going to lose your native plants.” Experienced contractors do regular, targeted herbicide treatments to get rid of invasives that cannot be hand managed.

While battling the invasives, you’ll find moments of gratification in coming across elusive native plants. For example, ghost pipes (Monotropa uniflora), which benefit from the ongoing restoration effort, may peek out of leaf litter with their pale white stems and papery flowers. Lacking chlorophyll, they survive as saprophytes, drawing nutrients from tree roots. Keep your eye out for the equally odd-looking Jack-in-the-Pulpit (Arisaema triphyllum) with its hooded flower. Fold back the hood to see its spike of tiny flowers. The plant is poisonous to humans, but some animals feed on its berries.

Steve may point out the native dogbane (Apocynum cannabinum), that grows in clumps like other bunch grasses. While it is attractive to many insects, Steve notes that this milkweed relative earns its name—it is indeed toxic to mammals.

Photo of the Dogbane plant
Dogbane (Apocynum cannabinum).

The taller native bottlebrush grass (Elymus hystrix) has feathery seed heads. Birds enjoy its grainy seeds. Another is poverty oat grass (Danthonia spicata). While deer resistant, poverty oat grass supplies forage for various insects. These are some of the plants that can transform a yard from turfgrass to habitat for native animals. As Steve says, “these grasses will be taller and won’t look like turf grass, but we have to change our thinking about what a yard can be. Many yards have empty spaces that you would not miss.” 

Photo of a tree sapling in a protective cage

At Glencarlyn Park, you may also encounter some native restoration plantings. Redbud saplings (Cercis canadensis) are enclosed in wire cages to protect them from grazing deer as they mature. 

You may be asked to wrestle the climbing porcelain berry (Ampelopsis brevipedunculata) off the cages to make sure the redbuds get enough access to light. Be careful that you’ve got the right plants, though, because porcelain-berry is closely related to the native grapevines (Vitis spp.) that are valuable to nesting birds. 

Steve’s lively conversation is so information-packed that time passes quickly and you may find yourself looking eagerly forward to the next invasives removal opportunity. 

Learn more on Steve Young’s blog: Plant Whacker, http://www.plantwhacker.com. You can also sign up on the ARMN Volunteer webpage for Arlington County for the Long Branch Park Invasive Plant Removal and other park sessions. The Glencarlyn weed removal event is monthly on Sunday afternoons. 

Additional Wildlife Information (All forms of life that are wild, including plants, animals, and microorganism – Natural Resources Service)

Jack-in-the-Pulpit (Arisaema triphyllum):

One of the more distinctive plants on VA forest floors, Jack-in-the-Pulpit is native to all of eastern North America. Each plant produces a large, fleshy flower on its own stalk, adjacent to a separate stalk with several leaves. The way the flowers’ sheath (the “spathe”) encloses and curls over the flower stalk (the “spadix”) explains its common name. The spadix (Jack), however, is actually hermaphroditic, able to produce male flowers, female flowers, or both. A plant growing just male flowers on the spadix has a hole at the base of the sheath that allows pollinators to do their job and then escape through the bottom. The plants growing just female flowers, however, lack the hole; the theory is that insects get trapped and pollinate as they writhe around.

Learn more on the USFS website about Jack in the Pulpit.

Revitalizing the Pollinator Garden at the Buddie Ford Nature Center

Text and photos by Leslie Cameron

Arlington Regional Master Naturalists joined Extension Master Gardeners and community volunteers on July 17th in an ongoing effort to revitalize the pollinator garden next to the Jerome “Buddie” Ford Nature Center in Alexandria

This hillside pollinator garden contains native plants local to the area, including Upland Ironweed (Vernonia glauca), Sundrops (Oenothera frutica), and various Milkweed species (Asclepias spp.). Many of these inhabit the nearby Dora Kelley Nature Park and the Holmes Run Gorge. The pollinator garden has for several years been an important part of the work the Nature Center to share the wonders of nature with the community, as well as to support our local pollinators.

Photo of the pollinator garden
Pollinator garden at the Buddie Ford Nature Center at the beginning of the day on July 17th.

Unfortunately, the garden has gradually accumulated many invasive species and other weeds that have been crowding out the native plants. Recognizing the need for some serious TLC, Master Naturalist Valerie LaTortue collaborated with Master Gardeners Bob Besse, Mary Lou Leary, and Scarlett Swan to begin a rejuvenation project. They met several times this spring and realized that they needed a lot more help. So, Valerie organized the July 17th volunteer garden day and reached out to other Master Naturalists, Master Gardeners, and park neighbors to pull invasive plants and other weeds from the garden, clear paths, and spread mulch. 

Photo of volunteer Valerie LaTortue weeding in the garden
Master Naturalist Valerie LaTortue, organizer of the volunteer garden day, pulling invasive plants and weeds in the pollinator garden (and too focused on the weeds to look up for a photo 😊).

Although it was a hot day, the volunteers worked tirelessly to uproot stubborn invasive plants and weeds and clear the pathways, filling many yard-waste bags.

Some roots were tough to remove, but the volunteers were tougher!

Photo of volunteer holding a weed with a long root
Nick Nichols wins the prize for longest root pulled—a nasty porcelain berry vine.

And for breaks, volunteers enjoyed snacks, cold water, and Valerie’s herb iced tea under a canopy on the deck overlooking the garden. 

Photo of two containers of iced tea
Valerie’s herb iced tea.

Best of all, the volunteers could enjoy the fruits of their labor right away! Check out Valerie’s video of accomplishments of the day:

Photo of a dirt pathway through the garden
Success! A pathway is now cleared of invasive plants and other weeds in the pollinator garden.

The ongoing work to rejuvenate the pollinator garden is part of a long-term plan to redesign and replant the garden and increase its access to and public education value for the community. In addition to supporting pollinators and improving the ecosystem, Master Naturalists, Master Gardeners, and other area volunteers are helping to reclaim this treasured public education resource for visitors to the Buddie Ford Nature Center and Dora Kelley Park.

More volunteers are needed and welcome! During the foreseeable future, volunteer days are scheduled each Saturday from 9:00-11:00 am (https://armn.org/volunter-alexandria/). Instructions, tools, and refreshments are provided. Volunteers should bring gloves, sunscreen, and insect repellent, and a favorite digging tool if they like.

Paddling for Litter on Four Mile Run Stream

by Devin Reese

Arlington Regional Master Naturalists find ways to improve their local ecosystems not only on land, but also on the water. The Four Mile Run Conservatory Foundation hosts regular stream clean-ups by kayak. All you need to bring is yourself, your enthusiasm for a cleaner stream, and a sense of humor about getting your feet wet. The program provides the boats, paddles, life jackets, gloves, and grabbers for fetching trash from the stream and tossing it into bins. 

Photo of volunteers on kayaks in four mile run creek
The June 5th flotilla of Four Mile Run cleanup volunteers included community members as well as three Arlington Regional Master Naturalists. Photo by Kurt Moser.

When you set out, it’s natural to wonder whether you’ll be able to find and retrieve trash. While it’s not a competition, something about the standardized bin strapped to each kayak ignites your ambition to fill it up fast. Some pickups are quick; your grabbers readily clasp a soda bottle perched on the grassy bank. Some of them take time; plastic bags seem to have a way of burrowing into the soil so that what you think is a quick fetch turns out to be a long tug of war. 

Litter encompasses everything from a multitude of water bottles and cans to larger items like gallon jugs and clothing. Elusive litter shows up in small scraps, such as gum wrappers or bottle labels. Occasionally, you’ll land a big, impressive piece of trash. Those mega-finds have their pros and cons. The Four Mile Run cleanup lore includes a story about the retrieval of a full-sized shopping cart, which had to be strapped on the front of a kayak.

Photo of a bin filled with trash from the creek
Litter bounty is strapped to the front of a kayak. Photo by Devin Reese.

When you’ve filled your bin or fetched an item worthy of showcasing, you paddle for the put-in, a gently sloping dirt ramp where the President of the Four Mile Run Conservatory Foundation, Kurt Moser, waits. He has big trash bags in hand to relieve you of your treasures and get you turned around and back onto the stream as efficiently as possible. Lest it sound like all work and no play however, Kurt also offers granola bars and drinks! 

Each time you launch, you have exciting choices to make—upstream or downstream, right bank or left. Whether you paddle up towards Shirlington or down towards the Potomac, you find plenty of opportunities to load the bin. And you may also find opportunities to chat with people, share what you’re doing, and learn more about how people enjoy Four Mile Run as a natural area. 

Photo of a volunteer holding a channel catfish
Liam proudly displaying the Channel Catfish (Ictalurus punctatus) he caught with his dad, Robert, by the Four Mile Run bridge.

While nestled in an urban area, Four Mile Run stream gets lots of day use by people fishing, jogging, watching birds, and even taking a dip.

After a couple of hours of paddling the stream, especially if it’s a hot day, you may drift into reflections about whether you’re really making a difference. Plucking the litter from the stream bottom or streamside vegetation can be tedious and slow-going. And, as ARMN volunteer Marilynn Lambinicio said, “You won’t necessarily see a change from one cleanup session to another, since litter continues to enter the stream from lots of upstream development.” 

Photo of a volunteer picking up litter while in a kayak
Arlington Regional Master Naturalist Marilynn Lambinicio dumps litter into a bin. Photo by Devin Reese.

Don’t lose sight of the purpose however, as the reward comes in the collective results. The session ends with the flotilla of kayaks pulling back into the put-in area, washing boats, snacking some more, stowing equipment, and amassing the litter loot. At the most recent June 5th kayak cleanup, in just a couple of hours, a group of just eight volunteers retrieved 171 pounds of litter from the Four Mile Run Stream!

Photo of bags of litter collected during the stream clean up

Don’t lose sight of the purpose however, as the reward comes in the collective results. The session ends with the flotilla of kayaks pulling back into the put-in area, washing boats, snacking some more, stowing equipment, and amassing the litter loot. At the most recent June 5th kayak cleanup, in just a couple of hours, a group of just eight volunteers retrieved 171 pounds of litter from the Four Mile Run Stream!

That’s approximately 20 pound each, a phenomenal haul that left the stream looking a lot more inviting for recreation and wildlife.

Would you like to participate in one of these kayak cleanups? If so, see Four Mile Run Conservatory Foundation, or email: info@fourmilerun.org for more information.

Wildlife
Wildlife includes all forms of life that are wild, including plants, animals, and microorganisms according to the Natural Resources Service.

The Channel Catfish (Ictalurus punctatus) is one of the most common fishes caught on Four Mile Run Stream. While native from Canada to Mexico through the central U.S., Channel Catfish were introduced to the eastern U.S. more than a century ago. First observed in Virginia water bodies in 1969, Channel Catfish became established and are now prized for aquaculture and recreational fisheries. Their success stems from opportunistic feeding habits (choosing whatever is available), prolific reproduction, disease resistance, and tolerance for a range of environmental conditions from fresh to brackish waters. While accepted as an important food fish in this region, Channel Catfish may be causing declines of native animals such as crayfishes through competition and predation.

Learn more about the Channel Catfish on the United States Geological Service website.

Two Honors! Glenn Tobin Earned the 2020 Bill Thomas Volunteer Award, and ARMN is presented the Virginia Chapter of the Wildlife Society’s 2021 A. Willis Robertson Award

Glenn Tobin is the 2020 Bill Thomas Park Volunteer Award Winner

Photo of Glenn pulling kudzu vine in front of a creek
Glenn conquering invasive kudzu from Windy Run Park. Photo courtesy of Toni Genberg.

On April 20, 2021, Glenn Tobin received Arlington County’s Bill Thomas Park Volunteer Award for the year 2020. The award recognizes an individual or group whose efforts show ongoing dedication and tangible benefit to Arlington’s natural resources, parks, and public open spaces.

Glenn has been an ARMN member since 2016 and a Trail Maintainer with the Potomac Appalachian Trail Club (PATC) since 2015. For years, he removed invasive plants at Windy Run Park and the adjacent Potomac River waterfront in the George Washington Memorial Parkway. Because of his work alone and with other volunteers, significant natural areas are recovering and becoming more beautiful and biodiverse. In 2020, Glenn raised money and worked with the PATC and the National Park Service (NPS) to rebuild the stone stairway that connects the Windy Run park trail to the Potomac Heritage Trail along the river, improving access for many people. Then, inspired by the reemergence of diverse native flora at Windy Run and along the Potomac, Glenn began working with experts in ecology, botany, and natural resources to create the website, Natural Ecological Communities of Northern Virginia, which provides information about the local natural plant communities to help make better plant selections for ecological restoration purposes in Northern Virginia, Washington D.C., and close-in Maryland. As a result of Glenn’s leadership, ARMN is adopting natural plant communities as a framework for park restoration, in collaboration with local jurisdictions. This work will have lasting impact on restoration planning throughout the County and on selection of plant species for the County’s native plant nursery.

Some of Glenn’s other work includes helping lead Weed Warrior Training with the NPS, assisting in leadership for Park Stewards, and mentoring others who share deep passion for helping restore natural areas in Arlington County and beyond.
(From: The Arlington, VA webpage: “Arlington Honors Park Volunteers”.) 

In a clip from the April 20, 2021 Arlington County Board Meeting, Board Member Karantonis describes Glenn’s accomplishments followed by an address from Glenn. In closing, Chair de Ferranti congratulates Glenn and 2019 Bill Thomas award winner, Elaine Mills: https://youtu.be/oPU84gCj9Lw.

ARMN is selected for the Virginia Chapter of the Wildlife Society’s 2021 A. Willis Robertson Award

On January 29, 2021, ARMN was selected as the 2021 recipient of the A. Willis Robertson Award from the Virginia Chapter of The Wildlife Society for its work on public outreach and education related to deer management. The award honors a wildlife non-professional or group that has exercised outstanding conservation practices on their own land or have made significant contributions to conservation activities in the Commonwealth.

Photo of a plaque in the shape of Virginia for the A. Willis Robertson Award
The Virginia Chapter of The Wildlife Society’s 2021 A. Willis Robertson Award for ARMN. Photo courtesy of Marion Jordan.

In the last few years, members of ARMN led by Bill Browning have spearheaded public education to alert the community to the effects of deer browsing and begin the process of addressing barriers to developing an effective and humane program to control deer population in Arlington County. (See armn.org blog piece, “White-tailed Deer and Forest Health in Northern Virginia” that addresses how deer impact our forests.) The team worked on deer browse surveys, major outreach events with the Virginia Native Plant Society, the Deer Advisory Council for Northern Virginia, Arlington’s Urban Forestry and Environmental Services departments, and in 2019, with regional experts from VA, MD, and DC to create a volunteer training and public presentation that has been delivered over 40 times in the past two years.

Photo of ARMN volunteer Bill Browning
Bill Browning. Photo courtesy of Toni Genberg.

Bill (the 2018 winner of the Bill Thomas award) and the other volunteers have also addressed Arlington County Board members, School Board members, the County Manager, the Chair of the Department of Parks and Recreation, and the Acting Chief of Police. Bill also made presentations to Park and Recreation department employees and to several Arlington County civic commissions who have supported this message with letters to the County Board.

They also talked to civic/neighborhood associations, garden clubs, Extension Master Gardener volunteers, local TV and social media, and spoke at regional parks and conservancy, and hunting club meetings. This outreach has done much to bring the issue forward, engage stakeholders, and provide county decision-makers with sound, unbiased information for their consideration of a deer management plan.

ARMN is excited for this honor and opportunity to credit members like Glenn Tobin for their instrumental work to benefit our local natural environment.

The Virginia Opossum: An Extraordinary Marsupial in Our Own Backyards

by Sandy Sohns

The Virginia opossum is much maligned, and has a reputation as being a repulsive, aggressive, dirty, garbage-eating pest that should be avoided or killed. Sadly, it is misunderstood and is unappreciated for its contribution to the environment, public health, and science.

The Virginia Opossum (Didelphis virginiana) is one of the oldest surviving mammals on the planet, and the only marsupial found in North and Central America, Mexico, and Canada. 

In 1608 in Jamestown, Virginia, John Smith first observed and described the opossum as the size of a cat with the tail of a rat and the head of a pig.

Photo of an opossum
The Virginia opossum is North America’s only marsupial. Image Credit: David Cappaert, Bugwood.org, CC BY NC 3.0.
Photo of an opossum
Photo by Glenn P. Knoblock. Courtesy of Forest Preserve District of Will County.

Males are usually larger than females. They weigh from 4-15 pounds and are 2-3 feet long, including the tail. Opossums have hairless black or white ears, black eyes, a triangular shaped head with a long white face, a pink nose, and mostly dark gray fur. They have 50 teeth, the most of any marsupial. Their front toes have a span of 180 degrees and their opposable great toes on their hind feet act as thumbs and help them grasp and climb. Their scaly mostly hairless prehensile tail also helps with climbing, provides balance, as well as carrying leaves, grass, twigs, or other material for nesting.

Photo of three opossums hanging by their tails
Credit: Frank Lukasseck/Corbis, backyardzoologist.wordpress.com. CC BY NC SA 3.0.

Opossums are generalists, adapting to a wide variety of habitats such as deciduous forests, open woods, marshes, streams, and urban and suburban areas. They move from an area when water and food are not available. They don’t hibernate but they do slow down in cold temperatures; their hairless ears, nose, and tail are susceptible to frostbite. Opossums are not destructive in creating habitat: they don’t dig holes or build burrows. Rather, they’re opportunistic in selecting living arrangements made by other animals or seeking shelter in garages or under sheds. Opossums are not territorial but can be confrontational during mating season or if encountering individuals in their current habitat.

Opossums are nocturnal, solitary, independent, and do not initiate an attack on animals larger than themselves including humans. If confronted by a perceived threat, its offense, which is really bluffing, is to open its mouth showing its teeth, drool, growl, hiss, belch, scream, or screech to scare away whatever is frightening them.

Photo credit: http://www.maxpixels.net. CC0 (Public domain).

If stress increases, their defense—which is an involuntary physiological response—is to collapse. This is what is often called “playing ‘possum.” Their heart rate and respiration decreases, eyes are open or slightly closed, mouth is open, drooling is evident, defecation and urination can occur and if that isn’t enough to ward off whatever is bothering them, they can excrete a foul-smelling green liquid from their paracloacal glands near the base of the tail. This coma-like state can last from a few minutes to 4 or 6 hours.

Photo of an opossum playing dead
Opossum playing dead on back porch of apartment building. Photo by John Ruble. Wikimedia (Public domain).

They are meticulous groomers to keep their fur clean and dry. And it is estimated that they can consume upwards of 5,000 ticks per year. Females are especially fastidious before and after giving birth.

Opossums are omnivores and eat whatever is available including fruit, nuts, insects, frogs, rodents, grass, pet food, garbage, and carrion. They are referred to as “nature’s sanitation engineer” or “nature’s cleanup crew.” Their keen sense of smell and ability to remember where to find food is second only to humans.

They have a low body temperature which is unsuitable for the rabies virus and they are resistant to venomous snake bites due to a naturally occurring protein in their blood, the Lethal Toxic Neutralizing Factor (LTNF) which binds and neutralizes the venoms. This is scientifically important and the NIH’s National Center for Biotechnology Information has found LTNF to be a potent antidote for animal, plant, and bacterial toxins including scorpion and honeybee stings, plant-derived ricin, and botulism toxins.

Opossums have a short life span of 1-2 years. Motor vehicle accidents, hunting and trapping, disease and parasites, exposure and starvation all contribute to their brief existence. While their shy demeanor and proclivity for being killed by cars during their nocturnal food hunts implies decreased intelligence, they outperformed rats and cats in maze testing.

Their reproductive cycle is the shortest of any mammal, 12-13 days, with usually 2 litters a year between December and June. Females may bear as many as 25 babies (also called joeys like their distant kangaroo cousins) but the average survival rate is only 7-9 young. The reasons for this high mortality are many: the embryonic newborns are light pink, blind, about 1/2 inch long, and weigh 0.006 of an ounce. While they have deciduous claws on their front feet to climb up into the pouch, once there, they need to locate one of only 13 teats—some of which will not be viable. Those who make it will remain in the pouch for about 10 weeks, then gradually begin to leave and return to the pouch, and finally be completely weened by about 13 weeks. They stay with the mother for another 3 to 4 months, becoming stronger and independent. Around 7 or 8 months they become sexually mature, and then the mating season begins again.

Photo of an opossum mother with babies on her back
Opossum with babies. Jim Rathert. Photo by MDC Staff, courtesy of Missouri Department of Conservation.
Photo of mother opossum with two babies on her back
Photo by Monica R./Flickr Attribution 2.0 Generic (CC BY 2.0)

The Virginia opossum is indeed a remarkable animal with many distinctive characteristics that is worthy of respect and protection.

References

Krause, William J. and Krause, Winifred A. The Opossum: Its Amazing Story, Research Gate, January 2005. www.researchgate.net/publication/265347494_The_Opossum_Its_Amazing_Story 

“Virginia Opossum Didelphis Virginiana,Nature Worksnhpbs.org/natureworks/opossum.htm 

Kirchner, Jane. “Opossums: Unsung Heroes in the Fight Against Ticks and Lyme Disease,” National Wildlife Federation. June 13, 2017, blog.nwf.org/2017/06/opossums-unsung-heroes-in-the-fight-against-ticks-and-lyme-disease/ 

Debczak Michelle.“13 Facts About Opossums.” Mental Floss. June 8, 2018, www.mentalfloss.com/article/544902/facts-about-opossums

“Creature Feature: Opossums Are Nature’s Pest Control,” The Buzz, March 1, 2019, www.reconnectwithnature.org/news-events/the-buzz/opossum-creature-feature