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Species · Pennsylvania · BBS 2026 Release · 1966–2025

Carolina Chickadee Population Trend in Pennsylvania

All statesForest birds

Carolina Chickadee in Pennsylvania has surged: up 836% on the route-weighted index since 1968.

+836%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 →
41Routes 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 Carolina Chickadee 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 →

Carolina Chickadee has surged in Pennsylvania: up 836% on the route-weighted index since 1968.

Carolina Chickadee Population Forecast in Pennsylvania

If the recent trend holds, Carolina Chickadee in Pennsylvania is projected to rise about 62% by 2030 — from 0.91 in 2025 to a central estimate of 1.5 (95% range 0.96–2.0). A 5-year backtest shows a typical error of ±60.6%, with 20% of held-out values landing inside the 95% band.

+62%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 →
1.5Projected 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 →
0.96–2.095% 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 →
±60.6%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, Carolina Chickadee in Pennsylvania is projected to rise about 62% by 2030 — from 0.91 in 2025 to a central estimate of 1.5 (95% range 0.96–2.0). A 5-year backtest shows a typical error of ±60.6%, with 20% 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 →
20261.40.881.9
20271.40.901.9
20281.40.921.9
20291.40.941.9
20301.50.962.0

Carolina Chickadee Survey Routes in Pennsylvania

Routes recording Carolina Chickadee 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 →
West Grove1619961971
Jacobus1220251986
Clear Spring1120251988
Doe Run1120251969
Mt Gretna 2920222001
Brunnerville920092009
Duvall820211974
Drehersville 2820252015
Stoneybreak820252007
Plesant Grov720241967
Middletown620251973
Beaver520251998
Mt Gretna520001988
Mount Joy420251978
Chatham420251997
Carsonville419921985
Pottstown419871986
Leola320251998
Landisburg320252007
Jeannette220232002
Doylesburg220192013
Akron219971997
Bendersville220231990
Peters Mt219751975
Collegeville220241971

Carolina Chickadee Population Trend in Other States

alabamaarkansasdelawarefloridageorgiaillinoisindianakansaskentuckylouisianamarylandmississippimissourinew-jerseynew-yorknorth-carolinaohiooklahomasouth-carolinatennesseetexasvirginiawest-virginia

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