Starting in December of 1988, the Lloyd Center began using waterbird surveys of Allens Pond estuary in Dartmouth to assess the importance of the system to American Black Ducks (Anas rubripes), a migratory “dabbling duck” species that relies almost exclusively on estuaries for food during winter. Many other waterfowl species flock to coastal water bodies during winter when freshwater freezes over further north.
These include the familiar Canada Goose (Branta canadensis) and Mute Swan (Cygnus olor) which may breed locally and are a common site at a nearby park, and the Mallard (Anas platyrhynchos), our most familiar dabbler potentially seen at nearly any permanent freshwater system. These three species dwell in close proximity to humans and often feed on land. Gadwall (Anas strepera), Northern Pintail (Anas acuta), and American Wigeon (Anas americana) are less common dabblers that may be seen in certain estuaries.
A diversity of diving ducks including Bufflehead (Bucephala albeola), Common Goldeneye (Bucephala clangula), Red-breasted Merganser (Mergus serrator), both Lesser and Greater Scaup (Aythya spp.) and Ruddy Duck (Oxyurab jamaicensis) migrate long distances and are especially dependent upon ice-free waters in winter due to their feeding habits which exclusively diving for prey or vegetation.
Through time a regional assessment of all waterfowl utilizing flowing estuaries and coastal ponds from the Sakonnet River in Rhode Island to Apponagansett Bay in Dartmouth evolved and became the “Annual Lloyd Center Winter Waterfowl Survey”. This survey includes twenty-one systems within the towns of Dartmouth and Westport in MA, and Tiverton and Little Compton in RI. Habitats represented include tidally unrestricted estuaries (four rivers), tidally unrestricted salt marshes (four marshes), restricted estuaries (four ponds, one marsh), intermittently flooded salt ponds (seven salt ponds), and ponds containing mostly freshwater (two ponds).
Each winter an early December (early meteorological winter) and late January or early February survey (late meteorological winter) are conducted, the two surveys accounting for differences in both migration schedules of waterfowl species and ice coverage that is based upon weather patterns. On the two Sundays when surveying takes place, volunteers identify and count all individuals present at their respective sites, and estimate the percentage of ice coverage, given that ice is a limiting factor for waterfowl abundance.
CLICK HERE (PDF format) for totals from 2000 to the most recent count; they are divided into years comprising the waterfowl season (e.g. 00/01 = Dec 2000, Jan/Feb 2001), totals for each month, totals for each waterfowl season, and approximate ice coverage present during the December and January/February counts.