BirdAnalyst
Species · Pennsylvania · BBS 2025 Release · 1966–2024

Yellow Warbler Population Trend in Pennsylvania

All statesForest birds

Yellow Warbler in Pennsylvania has increased: up 26% on the route-weighted index since 1968.

+26%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 →
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 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 35% by 2029 — from 7.5 in 2024 to a central estimate of 10 (95% range 5.6–15). A 5-year backtest shows a typical error of ±58.9%, with 60% of held-out values landing inside the 95% band.

+35%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 →
10Projected 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 →
5.6–1595% 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 →
±58.9%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 35% by 2029 — from 7.5 in 2024 to a central estimate of 10 (95% range 5.6–15). A 5-year backtest shows a typical error of ±58.9%, with 60% 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 →
2025105.415
2026105.515
2027105.515
2028105.515
2029105.615

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 →
Harmonsburg4620231966
Poyntelle3920241973
Duvall3720211974
Plesant Grov3620241966
West Grove3519961967
Jefferson2720241966
Roulette 22420242022
Hop Bottom2320241967
Austinville2220241966
Little Marsh1920241967
Akeley1819791966
Sigel1820241981
Sardis1819741967
Starlight 21820242000
Rush1620241970
Ferris Crnrs1520241966
Eldred1520221973
English Ctr1519891969
Waller1520241971
Millville1520241969
Honesdale1520241972
Starlight1519991970
Geeseytown1520241987
Ellenton1520241982
Ryde1420051970

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 2026-05-22.