2023 Winter Waterfowl Count Summary
Larry Cartwright, Compiler
The Winter Waterfowl Count, which ASNV sponsors, covers the Potomac River from Algonkian Regional Park in Loudoun County to Quantico Marine Base in Prince William County, as well as many inland bodies of water. The 2023 count was conducted on February 11 and 12 by teams in 15 sectors composed of 61 volunteers. They documented 34,797 individuals of 42 species. We tallied both traditional waterfowl (ducks, geese, and swans) and water-associated birds (grebes, cormorants, and waders).
Volunteer data shows that dabbling ducks were present only in low numbers. Even the normally ubiquitous dabblers had a poor showing. American Mallards, which five years ago would boast numbers well over 1,500, barely broke 1,000, and American Black Ducks that formerly had 800 to 900 individuals, had only 450 individuals in 2023. The other dabblers, including Northern Shovelers, Gadwalls, American Wigeons, and Northern Pintails, were in low numbers. The most numerous after Mallards and Black Ducks were Northern Pintails, with only 129 individuals.
Counts of Lesser Scaup, our most numerous diving duck, have fluctuated over the last five years, and at first blush give the impression of stability. That would seem to be justified by the large flocks of Lesser Scaup observed in the Potomac River, Occoquan Bay, and Belmont Bay in 2023. However, if we compare the 2018 numbers with 2023, we see a drop of 50 per cent in the winter population, from over 14,000 birds in 2018 to over 7,000 birds in 2023. Could the 2018 numbers be artificially high? Not likely. The 2015 survey tallied over 15,000 Lesser Scaup while the 2012 number was above 18,000. My analysis can change depending on how I view the figures, but it looks as if, despite the up and down fluctuations, that the Lesser Scaup trend is downward.
Other diving ducks are holding their own and seem to be a bright spot. Many of these birds prefer certain spots for where they spend the winter. Ring-necked Ducks seem to enjoy the area around Riverbend Park and Great Falls and inland bodies of water in western Fairfax County and Loudoun County. Volunteers observed 515 of the count’s 730 Ring-necked Ducks at these locations. A small flock of two dozen Common Goldeneye have occupied the area downriver of the American Legion Bridge over Interstate 495 for several years now. Want to see Canvasbacks or Redheads? Ft. Belvoir and Pohick Bay may provide your best opportunity.
As far as other waterfowl go, we only tallied 204 Tundra Swans during the 2023 survey. Generally, we get several hundred at the Great Marsh at Mason Neck alone. Now the birds seem to be more spread out between Mason Neck and Quantico, and perhaps some are moving further downriver beyond the scope of our survey.
Thanks to everyone who participated in the 2023 survey. It is amazing that over 60 people volunteered to go out on a winter’s day to count birds. We hope to see all of you back for the 2024 survey on February 3 and 4.
2021 Winter Waterfowl Count Summary
The Winter Waterfowl Count is sponsored by the Audubon Society of Northern Virginia. When begun in 2008, ASNV volunteers covered the Potomac River from Algonkian Regional Park in Loudoun County to Quantico Marine Base in Prince William County, as well as many inland bodies of water. In 2020 we expanded the survey by adding areas along the Potomac River in King George and Westmoreland County down to the mouth of the Potomac River where it empties into the Chesapeake Bay.
The 2021 Waterfowl Survey was conducted on February 6 and 7. The survey logged 33,364 birds, which is only 75% of the average for the previous five years. It also is the lowest count since at least 2016 despite adding the lower reaches of the Potomac River to the survey area in 2021. The 38 species found is also the lowest since at least 2016.
Common dabbling ducks had modest increases overall. Northern Pintails increased from 16 to 258, which is a big improvement, but still below historical averages, and Mallards increased from 1,140 to 1,685. However, Gadwalls declined from 204 in 2020 to 165, American Wigeons declined from 37 to only 14, and American Black Ducks decreased from 987 to 815.
Diving duck numbers generally increased. Canvasbacks increased from 291 in 2020 to 646 in 2021; Redheads increased from 47 to 155; and Ring-necked Ducks increased from 207 to 695, the highest number since 2018. Hooded Mergansers and Common Mergansers increased from 203 and 147 birds, respectively, in 2020 to 360 and 378 birds in 2021. Lesser Scaup were a particularly bright spot, increasing from 8,443 to 10,254, the highest count since 2018. However, Buffleheads declined from 1,931 to 512 and Ruddy Ducks declined from 4,930 to 2,688.
Among the large waterfowl, Tundra Swans increased from 397 to 422, but the 9,078 Canada Geese surveyed in 2021 is less than half of the number found in 2020 and only 2/3 of the average of 13,500 birds for the previous five years. The decline in Canada Geese accounts for about half of the total decline in birds surveyed in 2021.
The low numbers of waterfowl we have experienced in northern Virginia during the past three years might be attributed to the rapid decline of submerged aquatic vegetation (SAV) after large amounts of rain in the spring of 2018. The high water levels and sedimentation caused much of the SAV to die off, and it has taken time for it to return to the levels sufficient to support the normal population of wintering waterfowl in our area. Hopefully, the 2022 survey will reflect better overall numbers.
We owe special thanks to the 40 intrepid surveyors who participated in this year’s count and particularly to Larry Cartwright, who recruited and organized the surveyors, served on three survey teams, and compiled the results of all fourteen teams. The Winter Waterfowl Survey depends on our citizen scientists.
Raw Data Tallies from Previous Counts
2020 Winter Waterfowl Count
2019 Winter Waterfowl Count
2018 Winter Waterfowl Count
2017 Winter Waterfowl Count
2016 Winter Waterfowl Count
For older data, please contact us.