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Species · Pennsylvania · BBS 2025 Release · 1966–2024

Blackburnian Warbler Population Trend in Pennsylvania

All statesForest birds

Blackburnian Warbler in Pennsylvania has surged: up 774% on the route-weighted index since 1968.

+774%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 →
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 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 774% 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 22% by 2029 — from 1.7 in 2024 to a central estimate of 2.1 (95% range 1.5–2.6). A 5-year backtest shows a typical error of ±18.2%, with 100% of held-out values landing inside the 95% band.

+22%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 →
2.1Projected 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 →
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 →
±18.2%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 22% by 2029 — from 1.7 in 2024 to a central estimate of 2.1 (95% range 1.5–2.6). A 5-year backtest shows a typical error of ±18.2%, with 100% 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 →
20251.91.42.5
20262.01.42.5
20272.01.42.6
20282.01.52.6
20292.11.52.6

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
Ansonia1520242002
Roulette 21520242022
Ridgway1220181966
Whig Hill1020241966
Odin1020241976
Rasselas920221969
Duboistown920241996
Logue820231976
Broad Mtn.820241993
Marsh Hill720241983
N Pine Grove620241969
Russell City620241968
Poyntelle620241973
Ltl Pine Cr620241990
Ellenton520241982
Roulette520211977
Arnot520241993
Landisburg520241978
Sigel420241995
Betula420221987
Naginey420241974
Pottersdale320221969
English Ctr319891987
Laurel Hill320241978

Blackburnian Warbler Population Trend in Other States

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

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