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

Yellow Warbler Population Trend in Pennsylvania

All statesForest birds

Yellow Warbler in Pennsylvania has increased: up 36% on the route-weighted index since 1968.

+36%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 →
132Routes 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 Yellow 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 →

No notable trend signals for Yellow Warbler in Pennsylvania. See the full index history below.

Yellow Warbler Population Forecast in Pennsylvania

If the recent trend holds, Yellow Warbler in Pennsylvania is projected to rise about 20% by 2030 — from 8.4 in 2025 to a central estimate of 10 (95% range 5.5–15). A 5-year backtest shows a typical error of ±41.5%, with 100% of held-out values landing inside the 95% band.

+20%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 →
10Projected 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 →
5.5–1595% 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 →
±41.5%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, Yellow Warbler in Pennsylvania is projected to rise about 20% by 2030 — from 8.4 in 2025 to a central estimate of 10 (95% range 5.5–15). A 5-year backtest shows a typical error of ±41.5%, 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 →
20269.95.414
202710.05.415
2028105.515
2029105.515
2030105.515

Yellow Warbler Survey Routes in Pennsylvania

Routes recording Yellow 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 →
Duvall3720211974
Austinville3620251966
Plesant Grov3620241966
Poyntelle3520251973
West Grove3519961967
Jefferson3220251966
Starlight 22920252000
Honesdale2620251972
Harmonsburg2520251966
Hop Bottom2520251967
Roulette 22520252022
Beaver2220251969
Parkwood2220251967
Espyville2020251967
Sigel1920251981
Little Marsh1920241967
Waller1920251971
Akeley1819791966
Arnot1820251969
Sardis1819741967
Ellenton1720251982
Bow Bridge1620251969
Susquehanna1620251971
Geeseytown1620251987
N Washington1520251967

Yellow Warbler Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonrhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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