Winter Waterfowl

research-waterfowlSince December 1988, the Lloyd Center has surveyed wintering waterfowl in estuaries from the Sakonnet River in Rhode Island to Apponagansett Bay in Dartmouth, Massachusetts.

In what started as an effort to determine the importance of Allens Pond Estuary to the American black duck, a migratory dabbling duck relying exclusively on estuaries for its intertidal food source, the waterfowl survey has become both an enjoyable opportunity for long-time volunteers, and a crucial inventory of a premier bird assemblage in southeastern New England. Once bodies of freshwater freeze further north, many duck species breeding in forested freshwater wetlands depart south to our estuaries which rarely ice over. But estuaries do partially freeze, and tide and weather conditions can influence survey outcomes, so both an early December and a late January or early February survey are conducted. On the two Sundays, volunteers venture out to survey, then stop by the Lloyd Center for Mark Mello’s famous linguica stew, and provide us with their count results.

The winter waterfowl of our region can be divided into 4 basic groups and include what today are generally the most commonly encountered species: 
Swans: mute swan
Geese: Canada goose
Divers: bufflehead, red-breasted merganser
Dabblers: American black duck, mallard 

A much larger diversity of birds that exist at lower abundance levels can be found within the diver and dabbler groups such as Hooded Merganser, Ruddy Duck, American Wigeon, and Gadwall.

Winter Waterfowl trends update – December 2013 

Focusing on December surveys, the table below depicts the total number of birds counted for the last five years: 

Year       Total Waterfowl
2009        3,018
2010        3,674
2011        4,170
2012        4,824
2013        4,680

mallards russells millsAn average of 4,073 birds have been surveyed over this timeframe, a lower average than what would be expected for the January/February surveys (see update in January 2014).  However, this doesn’t necessarily make for a high January/February count. Extremely cold winters may cause extensive ice cover that forces flocks of birds to small pockets of unfrozen water, or may cause 100% ice cover in some water bodies, especially ponds.

This is one example of the type of variability that calls for a look at long term trends. Currently we are completing compilation of 25 years of winter waterfowl survey which will answer various questions and provide valuable information about waterfowl use of our region.

In comparing this December’s count to the survey of a year ago, we see a slight decline (-144) in birds but a similar result. A big drop in Canada geese (-680) was the lead contributor the decline, with bufflehead (-379) also down considerably from a year ago. Species showing increases however included American black duck (+401), mallard (+151) and mute swan (+130).

The top 5 sites respectively in terms of totals were as follows:
Briggs Marsh (534), Westport River West Branch (524), Slocums River (443), Cockeast Pond (398), and Allens Pond (332). Closely tied for the 6 slot were Apponagansett Bay (259) and Salters Pond(252). Only trace amounts of ice existed in these relatively vast, shallow estuaries.

Abundant species at these sites were as follows:
Briggs Marsh (Canada goose, rb merganser), West branch WR (black duck, bufflehead), Slocums River (black duck, mallard), Cockeast Pond (Mute Swan), Allens Pond (black duck), Apponagansett Bay (bufflehead), Salters Pond (black duck, Canada Goose).

Winter Waterfowl trends update – January 2014 

Turning now to the January portion of the survey, below are totals from the last five years, including the count just completed on Sunday, January 26, 2014. A column indicating an overall approximation of ice coverage is added for this “winter” survey: 

Year         Total waterfowl             Ice % (low, moderate, high)
2010           5,434                              moderate to high
2011           4,738                               moderate to high
2012           7,501                               low
2013           3,731                               high
2014           3,617                               high

An average of 5001 birds was counted over this timeframe, as expected a higher average than that observed in December. However, this past count was the lowest total ever recorded for the winter portion of the survey (and on the heels of one of the lowest December counts on record for 2013).

Prior to the recent surveys (2013, 2014) for this count, only once (1995 – 3653 total birds) have totals for the January/February count dipped below 4000 birds. For perspective, in both year 2000 and 2003 there were 14000+ and 11,000+ birds, respectively, and ice coverage was high. In those years, Canada Goose numbers were extremely high, at 10000+ in 2000, and 8000+ birds in 2003, comprising more than half the grand totals. For the 2014 count, goose numbers didn’t reach 1000 birds!

Canada Geese historically are the most abundant waterfowl species, and in any year may be seen resting on iced over water bodies, or may feed in nearby fields (and not be counted). So this common, adaptable species has great influence over survey results.

In comparing this year and 2013 for January, for which both waterfowl numbers and ice coverage were very similar, largest increases occurred for black duck (+255) and mallard (+174) with subtle increases observed for Hooded Merganser (+45), Common Goldeneye (+44), and Common Eider (+50). But the largest change was a decline in Canada Geese (-599) with northern pintail (-136) also declining to only 2 birds. It’s possible Canada Geese were feeding in fields nearby.

The top five sites respectively including grand total and dominant species were as follows:

Slocums River (657 – Mallard, Black Duck), Westport River the Let (424 – C. Goose, Black Duck), Westport River Harbor (414 – C. Goose, Bufflehead), Apponagansett Bay (354 -Mallard, Bufflehead), Nonquit Pond (300 – Mallard, C. Goose).

In closing, the 25th annual waterfowl season totals can be summarized as following:

Years             Fall (December)     Winter (Jan/Feb)         Total
2013/2014       4,680 birds              3,617 birds                 8,297 birds