BirdAnalyst
Species · Pennsylvania · BBS 2025 Release · 1966–2024

Northern Bobwhite Population Trend in Pennsylvania

All statesGrassland birds

Northern Bobwhite in Pennsylvania has collapsed: down 99% on the route-weighted index since 1968.

-99%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 →
93Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Northern Bobwhite 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 →

Northern Bobwhite has collapsed in Pennsylvania: down 99% on the route-weighted index since 1968.

Northern Bobwhite Population Forecast in Pennsylvania

If the recent trend holds, Northern Bobwhite in Pennsylvania is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–2.3). A 5-year backtest shows a typical error of ±4635.1%, with 100% 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 →
0.00Projected 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 →
0.00–2.395% 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 →
±4635.1%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, Northern Bobwhite in Pennsylvania is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–2.3). A 5-year backtest shows a typical error of ±4635.1%, 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 →
20250.000.002.3
20260.000.002.3
20270.000.002.3
20280.000.002.3
20290.000.002.3

Northern Bobwhite Survey Routes in Pennsylvania

Routes recording Northern Bobwhite 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 →
Gatchelville819901972
Sigel619951995
Big Flat519771966
Teepleville419921992
Roulette419881988
Mawr Glen419991999
Doubling Gap419771966
Clear Spring420001966
Peters Mt419761972
Labott419831966
Akron419891989
Poyntelle320011983
Geeseytown319971991
Mt Gretna319701966
Doe Run319921969
Stoneybreak320231993
Millville220081991
Shelocta219921992
Mifflintown219991966
Ephrata219881970
Clearfield219941967
Needmore219901966
West Grove219961966
Mars219911989
Brick Tavern220131990

Northern Bobwhite Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonrhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawashingtonwest-virginiawisconsinwyoming

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