BirdAnalyst
Species · Pennsylvania · BBS 2026 Release · 1966–2025

Black-and-white Warbler Population Trend in Pennsylvania

All statesForest birds

Black-and-white Warbler in Pennsylvania has surged: up 243% on the route-weighted index since 1968.

+243%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 Black-and-white 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 →

Black-and-white Warbler has surged in Pennsylvania: up 243% on the route-weighted index since 1968.

Black-and-white Warbler Population Forecast in Pennsylvania

If the recent trend holds, Black-and-white Warbler in Pennsylvania is projected to fall about 15% by 2030 — from 2.4 in 2025 to a central estimate of 2.0 (95% range 1.4–2.7). A 5-year backtest shows a typical error of ±30.2%, with 20% of held-out values landing inside the 95% band.

-15%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 →
2.0Projected 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 →
1.4–2.795% 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 →
±30.2%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, Black-and-white Warbler in Pennsylvania is projected to fall about 15% by 2030 — from 2.4 in 2025 to a central estimate of 2.0 (95% range 1.4–2.7). A 5-year backtest shows a typical error of ±30.2%, 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 →
20262.01.32.6
20272.01.32.6
20282.01.42.7
20292.01.42.7
20302.01.42.7

Black-and-white Warbler Survey Routes in Pennsylvania

Routes recording Black-and-white 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 →
Duboistown2220241987
Ansonia1620252002
Roulette1520211976
Laurel Hill1420251978
Mill Run1420251978
Tussey Mtn.1420251993
Ltl Pine Cr1320251990
Logue1120251976
Poyntelle920251973
Munson920251979
Pottersdale820251968
Cherry Sprs820251974
Susquehanna820251971
Ryde820051968
Broad Mtn.820251994
Ramsey720251968
English Ctr619891988
Rothrock Sf620191992
Odin520251974
Warrens Mill520251971
Honesdale420251972
Greentown420241973
Canadensis420251971
Scheafferstn420011966
Roulette 2420252022

Black-and-white Warbler Population Trend in Other States

alabamaarkansascaliforniaconnecticutdelawaregeorgiaillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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