BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Seaside Sparrow

PasserellidaeWetland birdsAmmospiza maritima

Seaside Sparrow has fallen sharply: down 55% on the route-weighted index since 1968.

-55%Since 1968TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
46RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Seaside Sparrow

The Seaside Sparrow (Ammospiza maritima) is a North American member of the New World Sparrows (Passerellidae). In this analysis it is grouped with the wetland birds.

Size
4.5–7.5 in long (12–19 cm) — a small songbird (typical for the family)
Habitat
Marshes, ponds, lakeshores and other freshwater wetlands.
Diet
Aquatic invertebrates, small fish, frogs and plant matter.
Range
Recorded on 46 Breeding Bird Survey routes across 12 states, most concentrated in the New England / Mid-Atlantic Coast.
Family
Passerellidae · Wetland birds

Notable Seaside Sparrow TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Seaside Sparrow. See the full index history below.

Seaside Sparrow Population Forecast

If the recent trend holds, Seaside Sparrow is projected to stay roughly flat through 2029, near 0.05 (95% range 0.02–0.08). A 5-year backtest shows a typical error of ±135.9%, with 20% of held-out values landing inside the 95% band.

n/aChange by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.05Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.02–0.0895% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±135.9%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Seaside Sparrow is projected to stay roughly flat through 2029, near 0.05 (95% range 0.02–0.08). A 5-year backtest shows a typical error of ±135.9%, with 20% of held-out values landing inside the 95% band.19662029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.050.020.08
20260.050.020.08
20270.050.020.08
20280.050.020.08
20290.050.020.08

Where the Seaside Sparrow Is Detected

BBS routes recording Seaside Sparrow, sized by most recent count.

Seaside Sparrow Population Trend by State

Seaside Sparrow population trend by state.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alabamainsufficient datan/a2
Delaware+742%196910
Florida-59%19756
Louisiana19×19737
Maryland+44%19683
Massachusettsinsufficient datan/a1
New Jerseyinsufficient datan/a2
New Yorkinsufficient datan/a2
North Carolinainsufficient datan/a2
South Carolinainsufficient datan/a1
Texas+145%19947
Virginia-71%19953

Seaside Sparrow Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Seaside Sparrow population trend by Bird Conservation Region.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Southeastern Coastal Plain-96%19689
New England / Mid-Atlantic Coast+116%196821
Gulf Coastal Prairie+80%197314

Seaside Sparrow Conservation Status

Our route-weighted index shows it down about 55% since 1968.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.