BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Bachman's Sparrow

PasserellidaeForest birdsPeucaea aestivalis

Bachman's Sparrow has fallen sharply: down 54% on the route-weighted index since 1968.

-54%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 →
323RoutesSurvey 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 Bachman's Sparrow

The Bachman's Sparrow (Peucaea aestivalis) is a North American member of the New World Sparrows (Passerellidae). In this analysis it is grouped with the forest birds.

Size
4.5–7.5 in long (12–19 cm) — a small songbird (typical for the family)
Habitat
Woodlands and forest edges, including wooded suburbs and parks.
Diet
Insects and spiders gleaned from foliage and bark, with seeds and berries in season.
Range
Recorded on 323 Breeding Bird Survey routes across 15 states, most concentrated in the Southeastern Coastal Plain.
Family
Passerellidae · Forest birds

Notable Bachman's 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 →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Bachman's Sparrow has fallen sharply in surveyed states: down 54% on the route-weighted index since 1968.

Bachman's Sparrow Population Forecast

If the recent trend holds, Bachman's Sparrow is projected to fall about 47% by 2029 — from 0.10 in 2024 to a central estimate of 0.06 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±37.4%, with 100% of held-out values landing inside the 95% band.

-47%Change 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 →
0.06Projected 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 →
0.00–0.1495% 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 →
±37.4%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, Bachman's Sparrow is projected to fall about 47% by 2029 — from 0.10 in 2024 to a central estimate of 0.06 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±37.4%, with 100% 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 →
20250.060.000.15
20260.060.000.14
20270.060.000.14
20280.060.000.14
20290.060.000.14

Where the Bachman's Sparrow Is Detected

BBS routes recording Bachman's Sparrow, sized by most recent count.

Bachman's Sparrow Population Trend by State

Bachman's 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 →
Alabama-3%196934
Arkansas-56%196919
Florida-48%196878
Georgia+162%196863
Kentuckyinsufficient datan/a13
Louisiana-95%196930
Mississippi+50%197018
Missouriinsufficient datan/a3
North Carolina-7%196814
Ohioinsufficient datan/a1
Oklahoma+208%19817
South Carolina-65%196924
Tennesseeinsufficient datan/a3
Texas-83%197014
Virginiainsufficient datan/a2

Bachman's Sparrow Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Bachman's 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 →
Central Hardwoods-78%196817
West Gulf Coastal Plain / Ouachitas-78%196958
Southeastern Coastal Plain-6%1968165
Appalachian Mountains-51%197012
Piedmont-43%196822
Peninsular Florida-57%196842

Bachman's Sparrow Conservation Status

Our route-weighted index shows it down about 54% 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.