Report on the 2025 Occoquan Bay Area Annual Butterfly Count

Photo: Eastern Tiger Swallowtail, Sheryl Pollock

Jim Waggener

0730, Sat., 28 Jun. 2025: Not the best of mornings for finding butterflies; sunless, oppressively humid, just the slightest of breezes, downright uncomfortable. But more than two dozen volunteers were ready for the challenge, forming small teams to cover Occoquan Bay NWR, and other promising sites nearby (Meadowood Recreation Area on Mason Neck, Occoquan Regional Park, the Metz Wetlands Preserve and Rippon Landing). Following a routine honed over decade of practice, every adult butterfly that could be identified would be recorded and, if unusual or rare, photographed. All done by sight, without capturing or harming any of the various swallowtails, sulphurs, skippers or other butterflies encountered.

This particular count was begun in 1990s to document the lepidoptera of a then U. S. Army facility slated for closure, both to draw public attention to the site’s unique nature and to generate support for its permanent protection. By the time the Occoquan Bay refuge was finally established in 1998 the count had taken on the form and routine that are followed today. Over the years, other sites with varied natural habitats were added. Certified in 2001 by the North American Butterfly Association, the Occoquan Bay-area Count presently encompasses the four sites (listed above) that are surveyed in a multi-year, citizen science project, long supported by the Northern Virginia Bird Alliance and other regional organizations.

Over the years, count results have varied considerably in numbers of species and individual butterflies. For example, 2005’s count resulted in 19 species and 114 individuals while 2013’s count resulted in 42 species and 1022 individuals. The count in 2015 resulted in 37 species and 1269 individuals, with the average over the past 24 years at 33.9 species and 593.6 individuals. Expectations for this year’s tally diminished as unfavorable conditions persisted until late morning. Less than an hour before count’s end, breaks appeared in the clouds, spurring heightened butterfly activity. While results from individual sites were not impressive, combined they were unexpectedly positive: 34 species and 828 individual butterflies.

In addition to the butterflies, this day’s count produced reports of a Mississippi Kite, confirmation of Blue Grosbeaks breeding, an uncommonly encountered Mole King Snake, other wildlife (Rough Greensnake, Box Turtle, Beaver, Cottontail, etc.) and plants (including first-of-season records of bloom).

In sum, another successful count and more records for the expanding base of data on these important natural sites. Certainly a tribute to the diversity and health of habitats across the various sites. A tribute as well to the skills and perseverance of the teams and leaders of today's count. A more difficult job than expected, perhaps, but exceptionally well done.

Learn more about butterfly counts and how you can join us!

Bald Eagles are Thriving but Face Challenges

Photo: Bald Eagle, Deborah Smith/Audubon Photography Awards

In an article published in the March 10, 2022 Mount Vernon Gazette Newspapers, Glenda Booth reported on a presentation about the state of Bald Eagles in our region.

Bald Eagle, Deborah Smith/Audubon Photography Awards

“Virginia’s tidal rivers are just loaded with bald eagles,” Jeff Cooper told 210 people attending the March 2 meeting of the Friends of Dyke Marsh.  These large raptors with an 80-inch wingspan regularly breed, nest, forage and migrate on and near rivers like the Potomac. People see bald eagles frequently at Dyke Marsh, Mason Neck and Fort Belvoir. Cooper is wildlife biologist with the Virginia Department of Wildlife Resources and has worked with birds for over 30 years and co-authored 17 papers. (Read the entire article here.)

The Importance of Wetlands

Photo: Mason Neck Park wetlands, Stephen Tzikas

Stephen Tzikas

My first exposure to wetlands was when I was a child in the 1960s. I frequently saw the inlet of the Raritan River filled with thousands of cattails while sitting in the backseat as my parents drove over the Victory Bridge connecting Perth Amboy and South Amboy, NJ. Much of those wetlands and floodplain around the river contained clay deposits that fueled a large terracotta industry in the 19th and 20th centuries. Some of the most interesting geological finds of these clay areas included gem grade amber with prehistoric insect inclusions. 

Later in life, as an engineer, I had some peripheral experiences with wetlands in engineering reviews of Federal construction. That took me to unique environments and terrains such as extreme cold regions, hot deserts, dams, and wetlands. But wetlands also caught my interest because of environmental concerns, which made up a significant portion of my early career.  Wetlands are protected and regulated. Many are found here in Fairfax County and local trails will bring you to them and the unique birds found within their boundaries. But before we note wetland birds, something should be said about the history behind protecting wetlands.

Wetland ecosystems protect and improve water quality, offer habitats, provide flood protection and erosion control, maintain surface water flow during dry periods, and present opportunities for recreation and aesthetic appreciation. By the way, those cattails I used to see so frequently are an iconic wetland plant found worldwide in a variety of aquatic ecosystems such as marshes, ponds, lakes, and riparian areas.  

Wetlands were considered an obstacle to development. They were often drained for farm land and construction. In the early 20th century, largely due to declining populations of ducks and geese, and the political pressure exerted by hunters, the federal government started protecting habitats for birds. The 1977 Clean Water Act was a big step forward for wetland protection. It protected waterways that resulted in protecting the wetlands that fed into them. Also in 1977, executive orders ended federal assistance for the draining and filling of wetlands.  A federal policy of “no net loss” of wetlands became the norm.  

Munsell soil test kit, Stephen Tzikas

Rutgers University has a regularly recurring one-day continuing education course at their wetlands location: the Environmental Education Center at Lord Sterling Park in Basking Ridge. The Introduction to Wetland Identification course teaches the use of Munsell soil test kits for wetlands. Although an online version of the course exists, the in-person version is better for the practical experience it delivers. Wetland soils are often grey (reduced) or dark brown to black. Use of the Munsell color system assures consistent classification. The course also makes use of dichotomous keys to identify wetland plants.

The eBird website posts bird sightings at wetlands throughout Fairfax County. Recently, as part of the Fall 2021 Fairfax Master Naturalist class, our field trip to Huntley Meadows wetlands in Alexandria recorded birds along a trail that was just under 2 miles. Birds spotted included: Canada Geese, Mallards, yellowlegs, herons, vultures, eagles, Belted Kingfishers, Northern Flickers, European Starlings, Red-winged Blackbirds, Northern Rough-winged Swallows, Ruby-crowned Kinglets and several types of hawks, woodpeckers, and sparrows. More common birds included Blue Jays, Carolina Chickadees, American Robins, Eastern Bluebirds, Carolina Wrens, crows, Tufted Titmice, and Northern Cardinals. In fact, Fairfax County Parks have documented more than 200 bird species in Huntley Meadows Park.

Huntley Meadows Wetlands, Stephen Tzikas

On another Master Naturalist field trip, we explored a different wetland at Elizabeth Hartwell Mason Neck National Wildlife Refuge. While we didn’t keep count of birds on this trip, it is known to have many types of birds throughout the year including Tundra Swans, Black Ducks, Northern Pintails, Mallards, and many others. High tide is the best time to go because the birds are closer to the shore and will be feeding more actively. 

Mason Neck Wetlands, Stephen Tzakis

June 2020

Photo: Yellow Flag Irises, Tom Blackburn

By Tom Blackburn

Last week, I decided to change my exercise routine by taking my kayak to Mason Neck State Park. But when I got into the boat my workout plans faded away, overwhelmed by the quiet beauty of a cloudless, balmy morning.  

Paddling slowly gave me an opportunity to fully experience my surroundings. The Osprey platform by the Visitor Center was empty.  This year, as happened in the two previous years, a pair of Canada Geese fought off the Ospreys and hatched a brood of goslings 60 feet above the ground. The geese are gone, of course; the young left the platform just a few hours after hatching for the hazardous trip to the ground. But by then it was too late for the Osprey to nest there. However, Osprey were nesting on several platforms in nearby Belmont Bay.

As I quietly made my way along the shoreline, a Bald Eagle flew up from a nearby log, carrying a fish; I had disturbed his breakfast.  Later, I watched a Great Blue Heron point its bill skyward, the better to let its morning catch slip down its throat. Hundreds of tiny fish rippled the water ahead of me, some taking briefly to the air to escape my boat. I watched a Green Heron land on the bank of Kane’s Creek and immediately melt into the shadows of the grasses along the shore.  Painted turtles completely covered some of the half-submerged logs, warming up in the morning sun. Early-season dragonflies zipped above the water.  

Painted Turtles, Tom Blackburn

Flowering plants also caught my attention.  Yellow flag irises are not native, but they have been in the area for more than 200 years, and they are spectacular on the edges of the park’s ponds. The golf ball-sized yellow blooms of spatterdock (a type of water lily with leaves standing well above the surface of the water) brightened their green leaves in the creek. And on the shore, I spotted early mountain laurel blooms.  In another week they will turn the hillside a delicate pink.  

Over the years in the park, I have watched fawns timidly venture to the water’s edge for a drink; a group of fox kits pounce into each rain puddle as they walked down a path followed by the vixen, while the male watched warily from the bushes; heard coyotes howling from the woods; surprised a Longnose Gar in the shallows; and been shepherded out of the creek by a beaver that repeatedly slapped its tail to  show its irritation at my presence.  Each time, I was moving slowly and observantly instead of focusing on getting from one place to another.  I am constantly reminded that in nature it’s not necessarily about the destination – it’s about the journey. I hope that you have opportunities to quietly observe the natural world and that it eases your mind and restores your soul, as it does for me.