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

Blue Jay Population Trend in Pennsylvania

All statesGeneralists

Blue Jay in Pennsylvania has increased: up 37% on the route-weighted index since 1968.

+37%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 →
137Routes 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 Blue Jay 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 →

No notable trend signals for Blue Jay in Pennsylvania. See the full index history below.

Blue Jay Population Forecast in Pennsylvania

If the recent trend holds, Blue Jay in Pennsylvania is projected to rise about 11% by 2029 — from 10 in 2024 to a central estimate of 12 (95% range 9.9–13). A 5-year backtest shows a typical error of ±11.3%, with 80% of held-out values landing inside the 95% band.

+11%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 →
12Projected 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 →
9.9–1395% 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 →
±11.3%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, Blue Jay in Pennsylvania is projected to rise about 11% by 2029 — from 10 in 2024 to a central estimate of 12 (95% range 9.9–13). A 5-year backtest shows a typical error of ±11.3%, with 80% 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 →
2025119.613
2026119.713
2027129.813
2028129.813
2029129.913

Blue Jay Survey Routes in Pennsylvania

Routes recording Blue Jay 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 →
Collegeville4020241971
Ryde2920051968
Scheafferstn2520011966
Mount Joy2420241978
Espyville2320241967
Roulette2220211970
Schwenksvill2220241988
Munson2120241979
Schaefferstown 22120242002
Lynch1920241968
Portersville1919881973
Duvall1920211974
Plesant Grov1920241967
Hometown1920241966
Mars1920241989
Jacobus1920241986
N Pine Grove1820241969
Ramsey1820231968
Little Marsh1820241967
Quakertown1819891970
Gatchelville1819901972
Sugar Grove1820241980
Waller1720241971
Beaver1720241969
West Grove1719961966

Blue Jay Population Trend in Other States

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

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