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Species · Pennsylvania · BBS 2025 Release · 1966–2024

Grasshopper Sparrow Population Trend in Pennsylvania

All statesGrassland birds

Grasshopper Sparrow in Pennsylvania has collapsed: down 87% on the route-weighted index since 1968.

-87%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 →
122Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Grasshopper Sparrow Trends in PennsylvaniaNotable 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 →

Grasshopper Sparrow has collapsed in Pennsylvania: down 87% on the route-weighted index since 1968.

Grasshopper Sparrow Population Forecast in Pennsylvania

If the recent trend holds, Grasshopper Sparrow in Pennsylvania is projected to fall about 85% by 2029 — from 0.39 in 2024 to a central estimate of 0.06 (95% range 0.00–0.67). A 5-year backtest shows a typical error of ±34.6%, with 100% of held-out values landing inside the 95% band.

-85%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 →
0.00–0.6795% 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 →
±34.6%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, Grasshopper Sparrow in Pennsylvania is projected to fall about 85% by 2029 — from 0.39 in 2024 to a central estimate of 0.06 (95% range 0.00–0.67). A 5-year backtest shows a typical error of ±34.6%, 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 →
20250.190.000.80
20260.150.000.77
20270.120.000.74
20280.090.000.71
20290.060.000.67

Grasshopper Sparrow Survey Routes in Pennsylvania

Routes recording Grasshopper Sparrow in Pennsylvania.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
N Washington620241967
Waterstreet620241968
Needmore519911966
Labott519831966
Schaefferstown 2520242002
Shrewsbury520231991
Warrens Mill420191971
Aspers419891968
Stoneybreak420241992
Akeley319791979
Austinville320191967
Portersville319751973
Rector319771966
Ryde320051968
St College320241969
Naginey320001973
Peters Mt319721972
Carsonville320231966
Normalville319691966
Doylesburg320192009
Berwick320231985
Clover219941981
Rasselas220111970
Rosecrans220181969
Ravensburg219791971

Grasshopper Sparrow Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.