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Species · Pennsylvania · BBS 2026 Release · 1966–2025

Eastern Bluebird Population Trend in Pennsylvania

All statesForest birds

Eastern Bluebird in Pennsylvania has surged: up 260% on the route-weighted index since 1968.

+260%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 →
135Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Eastern Bluebird 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 increasecomputed 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 →

Eastern Bluebird has surged in Pennsylvania: up 260% on the route-weighted index since 1968.

Eastern Bluebird Population Forecast in Pennsylvania

If the recent trend holds, Eastern Bluebird in Pennsylvania is projected to rise about 23% by 2030 — from 4.2 in 2025 to a central estimate of 5.2 (95% range 3.8–6.5). A 5-year backtest shows a typical error of ±9.4%, with 100% of held-out values landing inside the 95% band.

+23%Change by 2030TrendPercent 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 →
5.2Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
3.8–6.595% 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 →
±9.4%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, Eastern Bluebird in Pennsylvania is projected to rise about 23% by 2030 — from 4.2 in 2025 to a central estimate of 5.2 (95% range 3.8–6.5). A 5-year backtest shows a typical error of ±9.4%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20264.93.66.2
20275.03.76.3
20285.03.76.3
20295.13.86.4
20305.23.86.5

Eastern Bluebird Survey Routes in Pennsylvania

Routes recording Eastern Bluebird 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 →
Ryde2320051970
Jacobus1420251987
Stoneybreak1320251992
Mifflintown1220251972
Middletown1220251984
Needmore1219911966
Clover1020251981
Jefferson1020251966
Jeannette1020231981
Chatham1020251997
Greentown920241969
Geeseytown920251987
Doe Run920251975
N Pine Grove820251969
Millville820251970
Clearfield820251968
Sugar Grove820251980
Doylesburg820232009
Elizabethvil820251995
Berwick820251985
Sigel720251981
Virginia720251987
Pine Gr Mill720251967
Roulette 2720252022
Mount Joy720251990

Eastern Bluebird Population Trend in Other States

alabamaarizonaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.