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Species · Pennsylvania · BBS 2026 Release · 1966–2025

Acadian Flycatcher Population Trend in Pennsylvania

All statesAerial insectivores

Acadian Flycatcher in Pennsylvania has surged: up 249% on the route-weighted index since 1968.

+249%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 →
112Routes 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 Acadian Flycatcher 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 →

Acadian Flycatcher has surged in Pennsylvania: up 248% on the route-weighted index since 1968.

Acadian Flycatcher Population Forecast in Pennsylvania

If the recent trend holds, Acadian Flycatcher in Pennsylvania is projected to rise about 19% by 2030 — from 2.1 in 2025 to a central estimate of 2.5 (95% range 1.7–3.4). A 5-year backtest shows a typical error of ±12.3%, with 100% of held-out values landing inside the 95% band.

+19%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 →
2.5Projected 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 →
1.7–3.495% 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 →
±12.3%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, Acadian Flycatcher in Pennsylvania is projected to rise about 19% by 2030 — from 2.1 in 2025 to a central estimate of 2.5 (95% range 1.7–3.4). A 5-year backtest shows a typical error of ±12.3%, 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 →
20262.41.63.3
20272.51.63.3
20282.51.73.3
20292.51.73.3
20302.51.73.4

Acadian Flycatcher Survey Routes in Pennsylvania

Routes recording Acadian Flycatcher 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 →
Broad Mtn.1820251993
Tussey Mtn.1720251993
Landisburg1420251978
Laurel Hill1220251978
Mill Run1220251978
Jefferson920251966
Warrens Mill820251972
Stoneybreak820251992
Clear Spring720251966
Ravensburg619711971
Shelocta620241968
Margaret620251970
Clover520251981
Sardis519741970
South Mtn520251986
Beaver420251981
Duvall420211974
Martinsburg420251988
Williamsburg420251988
Peru Mills420251966
Needmore419911966
Rothrock Sf420191992
Espyville320251989
Sigel320251998
N Washington320251973

Acadian Flycatcher Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamarylandmassachusettsmichiganminnesotamississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomarhode-islandsouth-carolinatennesseetexasvirginiawest-virginiawisconsin

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