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Species · Pennsylvania · BBS 2025 Release · 1966–2024

Carolina Chickadee Population Trend in Pennsylvania

All statesForest birds

Carolina Chickadee in Pennsylvania has surged: up 763% on the route-weighted index since 1968.

+763%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 →
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 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 763% 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 63% by 2029 — from 0.91 in 2024 to a central estimate of 1.5 (95% range 0.99–2.0). A 5-year backtest shows a typical error of ±67%, with 20% of held-out values landing inside the 95% band.

+63%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 →
1.5Projected 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 →
0.99–2.095% 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 →
±67%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 63% by 2029 — from 0.91 in 2024 to a central estimate of 1.5 (95% range 0.99–2.0). A 5-year backtest shows a typical error of ±67%, with 20% 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 →
20251.40.901.9
20261.40.931.9
20271.40.951.9
20281.50.972.0
20291.50.992.0

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
Jacobus1320241986
Clear Spring1320241988
Mt Gretna 2920222001
Brunnerville920092009
Duvall820211974
Jefferson820241966
Plesant Grov720241967
Beaver620241998
Landisburg520242007
Mount Joy520241978
Mt Gretna520001988
Stoneybreak420242007
Carsonville419921985
Pottstown419871986
Doe Run420241969
Brunnerville 2320242010
Drehersville 2320242015
Chatham320241997
Middletown320241973
Leola220241998
Jeannette220232002
Doylesburg220192013
Akron219971997
Bendersville220231990

Carolina Chickadee Population Trend in Other States

alabamaarkansasdelawarefloridageorgiaillinoisindianakansaskentuckylouisianamarylandmississippimissourinew-jerseynew-yorknorth-carolinaohiooklahomasouth-carolinatennesseetexasvirginiawest-virginia

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