Important Bird Area: Allens Pond & Westport River Watershed
Site Summary
Nominated By
Jamie Bogart
Size
4,998 acres (five miles of beach) acres
Towns and Counties
Dartmouth, Little Compton, and Westport; Bristol, MA and Newport, RI
Ownership
State, municipal, private, Mass Audubon, The Trustees of Reservations
Major Habitats
Marine/tidal 40%, coastal beach 30%, salt marsh 20%, maritime heathland/sandplain grassland 10%
Land Use
Nature & wildlife, conservation/land trust, hunting & fishing, other rec., fisheries/ aquaculture, research, agriculture/ livestock
Serious Threats
Non-native invasive plants, predators
Minor Threats
Disturbance to birds and habitat
IBA Criteria
- Category 1: Sites important for long-term research and/or monitoring projects that contribute substantially to ornithology, bird conservation, and/or education.
- Category 2: Sites containing assemblages of species characteristic of a representative, rare, threatened, or unique habitat within the state or region.
- Category 3: Sites where birds concentrate in significant numbers in the breeding season, in winter, or during migration.
- 3a. Single-species Concentrations: The site regularly supports significant concentrations of a flocking species, but may not meet the thresholds above. The site should support a higher proportion of a species' statewide population (more than 1%, if known) than other similar sites.
- 3b. Waterfowl: The site regularly supports 500 or more waterfowl at any one time. The designation "waterfowl" includes birds such as loons, grebes, cormorants, geese, ducks, coots, and moorhens.
- 3c. Wading Birds: The site regularly supports 25 or more breeding pairs of wading birds or 100 or more foraging individuals (at one time) during migration. The designation "wading birds" includes bitterns, herons, egrets, and ibises.
- 3g. Seabirds: The site regularly supports 300 or more pelagic seabirds and/or terns or 3,000 or more gulls at one time. A pelagic site is the actual location being used by seabirds (e.g., Stellwagen Bank) and not the location from which an observer counts seabirds (e.g., Provincetown). Smaller concentrations of less common gulls such as Laughing or Bonaparte’s gullswill be considered. Human-made food sources for gulls such as landfills and sewage outflows will not be considered. The designation "seabirds" includes shearwaters, storm-petrels, fulmars, gannets, jaegers, and alcids.
- Category 4: Single-species Concentrations: The site regularly supports significant concentrations of a flocking species, but may not meet the thresholds above. The site should support a higher proportion of a species' statewide population (more than 1%, if known) than other similar sites.
- Category 5: Waterfowl: The site regularly supports 500 or more waterfowl at any one time. The designation "waterfowl" includes birds such as loons, grebes, cormorants, geese, ducks, coots, and moorhens.
Site Description
The Allens Pond/Westport River Watershed is contained mostly within Bristol County Massachusetts, but enters the eastern portion of Newport County Rhode Island. It is an intricate mix of riverine estuaries, tidal ponds, barrier beaches, salt marshes, and inner bay. Bay habitat includes portions of both Buzzards Bay and Rhode Island Sound. The Westport River, containing two significant branches, Rhode Island East and West is the largest of the three drowned river estuaries. Slocums River and Little River, both connected to Buzzards Bay at Potomska Point in Dartmouth, are the smaller river systems represented. Tidal Ponds include Quicksand Pond, Cockeast Pond, Richmond Pond, Allens Pond, Tunipus Pond, Georges Pond, and Briggs Marsh. Allens Pond is the most complex and diverse habitat included in the site and is connected to Buzzards Bay through a significant channel that shifts but allows the marsh to maintain its intertidal characteristics year-round. Agricultural fields, a warm-season grassland, shrub communities, a red maple swamp, and maritime oak forest border Allens Pond. The primary barrier beaches in Bristol County are: Horseneck, Little Beach, Barneys Joy, Briggs, Goosewing, and Demarest Lloyd. The smaller barrier beaches include the shoreline portions of Richmond Pond and Cockeast Pond, Acoaxet Beach, and Gooseberry Neck. The total river embayment area is 25,517 acres; the total open-water area of all the tidal ponds is 823 acres. Salt marsh, 1,558 acres collectively, borders all rivers and most of the ponds. The Barneys Joy and Little Beach sand spits form the "Allens Pond Complex" and both contain a significant concentration of nesting Piping Plovers and Least Terns during the summer months.
Current Conservation Status
Habitat diversity and the large number of birds attracted to the area were incentive for establishment of the Mass Audubon Allens Pond Wildlife Sanctuary within this site. All of the water bodies included in this site are, or have been in the past, subjected to long-term monitoring programs. The Plover and tern protection, management, and monitoring occurs each breeding season on all of the barrier beaches, and on Gooseberry Neck Island. This program has been in effect for over 15 years, and the Lloyd Center for the Environment and the Rhode Island Field Office of The Nature Conservancy publish the results each year. An annual winter waterfowl count is conducted in each water body within the site. A warm-season grassland establishment and research project is underway, within the Allens Pond sanctuary, to create native grassland habitat for declining grassland-dependant avian species. Allens Pond has been monitored for over 15 years for avian community structure and diversity. The Allens Pond Complex and Westport River Watershed are a mixture of state, town, and privately owned land, coastline, and wetlands.
Ornithological Significance
Shorebirds, seabirds, wading birds, waterfowl, passerines, and raptors all contribute to the nomination of the site. A large variety of waterfowl, such as American Black Duck 605, 1999; Bufflehead 808, 1999; Red-breasted Merganser 981, 1995; Ruddy Duck 737, 1998; Common Eider 10,000+, 1998; Double-crested Cormorant 1,500, 1998 winter within the area. The site has contained 9.25% of the statewide breeding population of the federally listed Piping Plover and 1.4% of the breeding population state-listed Least Tern. The federally listed Bald Eagle consistently winters in small numbers on the Westport River. The Northern Harrier also winters here, and two pairs are on record, as nesting over the last 15 years in 1990, 3.2% of the statewide population. A high concentration of Ospreys 86, 1995, breed within the site. Snowy Egrets and Great Egrets are particularly abundant with over 100 individuals recorded on any given summer count. Over 10,000 Tree Swallows were observed during fall migration. The Allens Pond Seaside Sparrow population is the largest in all of New England at 24 pairs in 1986 and >14 pairs in 2002. The regional high conservation priority species, Saltmarsh Sharp-tailed Sparrow (75-100 pairs, 1990) breeds in large numbers around Allens Pond. Additionally, a variety of other species, including a myriad of both state and regional high conservation priority species breed/winter/stopover within this site, including species such as American Oystercatcher, Willet, Whimbrel, Sanderling, Short-billed Dowitcher, Black-billed Cuckoo, Great-crested Flycatcher, Eastern Kingbird, Brown Thrasher, American Redstart, Eastern Meadowlark, and Bobolink.
Other Flora or Fauna of Significance
Fowler's Toad, Diamondback Terrapin at Slocums River and Allens Pond, and Monarch Butterfly migratory route.
Data Sources
See separate Bibliography, species lists including: references, several publications of Allens Pond research.