Breeding Bird Atlas 2 Species Accounts

Swamp Sparrow


Melospiza georgiana

  • Widespread and likely increasing
“The Swamp Sparrow is not a public character. He will never be popular or notorious. He is too retiring to be much in the public eye, and too fond of the impassable bog and morass to have much human company; and so he comes and goes unheralded and to most people unknown.” – Edward Howe Forbush, Birds of Massachusetts and Other New England States

The impassable bog and morass may be a poor place to entertain human company, but a densely overgrown wetland is very inviting to a Swamp Sparrow. Its slow, repeated trill is a common accompaniment to practically any slog through one of the Bay State’s marvelous marshes. Humankind’s destructive relationship with swampland and marshland may have been detrimental to Swamp Sparrows in the past, but the species’ recovery is showing promise for the future.

Historic Status

As wetlands go, so, it is likely, goes the Swamp Sparrow. No historical data exists to reflect the birds’ relationship to European settlement in Massachusetts, but what once was a landscape of free-flowing brooks and streams interrupted by beaver dams was quickly changed to one of millponds, farms, and villages — a transition that likely altered the breeding distribution of this species. Farmers “reclaiming” wetlands caused further changes, and the twentieth-century practice of filling wetlands for suburban development no doubt also created challenges for this species. As William Brewster noted, the presence of breeding Swamp Sparrows followed available habitat closely: “…one or two pairs nested every season in a little meadow just to the westward of the Cambridge reservoir on Highland Street, and others on a floating island in the pond at the rear of Mount Auburn. The Swamp Sparrows have long since disappeared from these localities, but in the Fresh Pond Swamps and at Rock Meadow they continue to appear as numerously as they have ever done within the period covered by my recollection” (Brewster 1906).

Atlas 1 Distribution

Swamp Sparrows were widespread in Atlas 1, and were found in 47% of the blocks surveyed. Their patterns of regional occupancy vary greatly. The higher ecoregions in the western part of the state had scattered Swamp Sparrow records, but percentages of occupied blocks were increased in the lower elevation areas. The Marble Valleys, Connecticut River Valley, and even the Lower Berkshire Hills all had 50% or better rates of block occupancy. The Worcester and Lower Worcester Plateaus each had strong showings from the Swamp Sparrow, as did the Coastal Plains. The Bristol/Narragansett Lowlands had less robust figures (44% occupancy), and the entire Cape and Islands had only 18 blocks, likely a function of that  region’s dry, sandy soil and largely saline rather than freshwater marshes.

Atlas 2 Distribution and Change

In general, Swamp Sparrows expanded their range in Massachusetts, increasing their footprint in all ecoregions except the Bristol/Narragansett Lowlands, and overall increasing to 59% block occupancy. There are scattered losses in other parts of the state, but the net loss in the Bristol/Narragansett Lowlands is notable. Swamp Sparrows remained stable on Cape Cod and the Islands, not showing a net loss or gain in occupied blocks, but abandoned Nantucket and Martha’s Vineyard while at the same time reaching farther east onto the extended arm of the Outer Cape.

 

Atlas 1 Map

Atlas 2 Map

Atlas Change Map

 

Ecoregion Data


 Atlas 1Atlas 2Change
Ecoregion# Blocks% Blocks% of Range# Blocks% Blocks% of RangeChange in # BlocksChange in % Blocks
Taconic Mountains637.51.3832.01.3213.3
Marble Valleys/Housatonic Valley2974.46.43589.75.7615.4
Berkshire Highlands2240.04.83665.55.91222.6
Lower Berkshire Hills2175.04.62683.94.3311.1
Vermont Piedmont741.21.51482.42.3216.7
Berkshire Transition1436.83.13382.55.41445.2
Connecticut River Valley2850.06.23553.85.736.3
Worcester Plateau4760.310.37888.612.81020.8
Lower Worcester Plateau4155.49.06378.810.3916.7
S. New England Coastal Plains and Hills15557.434.119669.332.2208.8
Boston Basin2035.74.42951.84.8916.4
Bristol and Narragansett Lowlands4744.310.33732.56.1-10-9.9
Cape Cod and Islands1813.24.01913.23.100.0
Statewide Total45547.0100.060958.7100.0809.7
 

Notes

Despite this apparent stability, the Breeding Bird Survey shows significant declines in the Swamp Sparrow’s abundance for the New England/Mid-Atlantic Region.

Breeding Bird Survey Chart