2012 Waterfowl Survey

The 2012 Waterfowl Survey took place on January 21-22 2012. Watch for results of the survey in the future.

2011 Waterfowl Survey Results

The 2011 waterfowl survey was conducted over the weekend of 22 and 23 January.  The survey effort consisted of 11 teams that provided complete coverage along the Potomac River from the Great Falls area down to Quantico and three teams that surveyed inland lakes and ponds.  It was partially sunny, but generally chilly, and survey teams reported that waterways were at least partially covered in ice.

In the four years that we have conducted the waterfowl survey in January, it is difficult to determine long term trends, but I have found some interesting fluctuations in some species. Three common waterfowl species, Canada Goose, Mallard and Common Mergansers showed large declines between 2009 and 2010, but returned to approximate 2009 levels in 2011.  They forage differently and I am still trying to determine the commonality for this occurrence.  The grazing Canada Goose dropped in numbers from approximately 15,000 in 2009 to roughly 8,700 in 2010, and bounced back to 14,300 in 2011.  The dabbling Mallard declined from about 3,000 in 2009 to 1,500 in 2010, but returned to nearly 3,000 in 2011. The diving Common Merganser plummeted from 1,450 in 2009 to slightly above 200 individuals in 2010, but numbered close to 900 in 2011.

Species showing significant declines between 2010 and 2011 were Gadwall, (declining from over 1,000 to slightly above 600), Canvasback (from nearly 850 to slightly below 500), and Ruddy Duck (from almost 1100 to around 650).  In contrast, the number of Hooded Mergansers tripled between 2009 and 2010 (from nearly 100 to 300).

If there are any immediate concerns for individual species at least for our region, I would draw attention to Northern Pintail and Green-winged Teal. The numbers have been persistently low since we have been conducting this survey.  Only two dozen Northern Pintail and 14 Green-winged Teal were documented in 2011.

Actual Talley for 2011

Larry Cartwright-compiler

2010 Waterfowl Survey Results

The 2010 waterfowl survey was conducted on 23 and 24 January 2010 and was the third year that the count was conducted in January after the Christmas Bird Count season.  Conditions were more favorable in 2010 than last year with more open water available.  This year 11 teams provided complete coverage along the Potomac River from the Great Falls area down to Quantico.  An additional four teams surveyed inland lakes and ponds.  This was three more teams than took to the field last year.

After three years of survey results, it is still difficult to establish a pattern or trend.  Indeed, the 2010 results were surprising in some cases.  Several common waterfowl species were greatly reduced in numbers when compared to last year.  Canada Geese (14,935 in 2009 to 8,724 in 2010); Mallards (2,975 in 2009 to 1,551 in 2010); Common Merganser (1,450 in 2009 to 221 in 2010).  The less common American Black Duck showed a similar reduction (1,356 in 2009 to 404 in 2010) and 70 percent of these birds were found at one location, the Great Marsh at Mason Neck, where they greatly outnumbered Mallards.   Pied-billed Grebes, although considered waterfowl in only the most generic sense, were also down (24 in 2009 to 3 in 2010).

There seems to be no easy explanation for these dramatically reduced numbers.  Hunting pressures seem unlikely since Canada Geese showed the most significant reduction in the northwestern portion of the Potomac River where little hunting occurs.  We might speculate that the scarcity of open water in 2009 concentrated the birds in fewer locations, making them easier to find, or that the major snowstorm in December 2009 caused a dispersal of waterfowl that continued into January 2010.  Perhaps, but some species showed major increases in numbers over last year.  Lesser Scaup (2,386 in 2009 to 8,478 in 2010); Ruddy Duck (238 in 2009 to 1,094 in 2010).  Others showed modest increases.  Gadwall (976 in 2009 to 1,014 in 2010); Ring-neck Duck (575 in 2009 to 659 in 2010).  Gadwalls are known to be increasing continent- wide according to organizations such as Ducks Unlimited that specialize in waterfowl trends.

Northern Pintails, a species that has caused concern in the past, also was represented better this year than last (22 in 2009 and 77 in 2010).  Finally, some species showed virtually no change from last year. How about Tundra Swans (408 in 2009 and 406 in 2010)!  Green-winged Teal are perhaps the only species that have displayed persistently low numbers during the January surveys (from a disappointing 102 in 2009 to a paltry 27 birds in 2010).

The most exciting find this year did not involve waterfowl at all.  It was the discovery of wintering  rails  (3 King Rails and 2 Virginia Rails) at Huntley Meadows.  King rails bred for the first time in over a decade at Huntley Meadows last year.  Virginia Rails also made their first ever documented breeding attempt at Huntley Meadows.  To have them wintering over as well is a real treat.

Actual Talley for 2010-1

Larry Cartwright-compiler