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Species · Pennsylvania · BBS 2026 Release · 1966–2025

Blackburnian Warbler Population Trend in Pennsylvania

All statesForest birds

Blackburnian Warbler in Pennsylvania has surged: up 702% on the route-weighted index since 1968.

+702%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 →
76Routes 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 Blackburnian Warbler 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 →

Blackburnian Warbler has surged in Pennsylvania: up 702% on the route-weighted index since 1968.

Blackburnian Warbler Population Forecast in Pennsylvania

If the recent trend holds, Blackburnian Warbler in Pennsylvania is projected to rise about 25% by 2030 — from 1.7 in 2025 to a central estimate of 2.1 (95% range 1.5–2.6). A 5-year backtest shows a typical error of ±15.3%, with 100% of held-out values landing inside the 95% band.

+25%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 →
2.1Projected 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 →
1.5–2.695% 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 →
±15.3%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, Blackburnian Warbler in Pennsylvania is projected to rise about 25% by 2030 — from 1.7 in 2025 to a central estimate of 2.1 (95% range 1.5–2.6). A 5-year backtest shows a typical error of ±15.3%, 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 →
20262.01.42.5
20272.01.42.5
20282.01.42.6
20292.01.52.6
20302.11.52.6

Blackburnian Warbler Survey Routes in Pennsylvania

Routes recording Blackburnian Warbler 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 →
Eldred2120221981
Lynch1220251968
Odin1220251976
Ridgway1220181966
Ansonia1220252002
Naginey1120251974
Russell City1020251968
Rasselas920221969
Broad Mtn.920251993
Duboistown920241996
Munson820251987
Roulette 2820252022
Ltl Pine Cr720251990
Whig Hill620251966
Cherry Sprs620251974
Ellenton520241982
Roulette520211977
Sigel420241995
Betula420221987
Logue420251976
Marsh Hill420251983
Arnot320251993
English Ctr319891987
Laurel Hill320251978
Pocono Summit 2320092004

Blackburnian Warbler Population Trend in Other States

connecticutgeorgiaindianamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinaohiorhode-islandtennesseevermontvirginiawest-virginiawisconsin

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