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Species · Pennsylvania · BBS 2026 Release · 1966–2025

Blue-headed Vireo Population Trend in Pennsylvania

All statesForest birds

Blue-headed Vireo in Pennsylvania has surged: up 52× on the route-weighted index since 1968.

52×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 →
100Routes 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 Blue-headed Vireo 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 Blue-headed Vireo in Pennsylvania. See the full index history below.

Blue-headed Vireo Population Forecast in Pennsylvania

If the recent trend holds, Blue-headed Vireo in Pennsylvania is projected to rise about 78% by 2030 — from 1.5 in 2025 to a central estimate of 2.7 (95% range 2.0–3.5). A 5-year backtest shows a typical error of ±30.3%, with 60% of held-out values landing inside the 95% band.

+78%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 →
2.7Projected 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 →
2.0–3.595% 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 →
±30.3%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, Blue-headed Vireo in Pennsylvania is projected to rise about 78% by 2030 — from 1.5 in 2025 to a central estimate of 2.7 (95% range 2.0–3.5). A 5-year backtest shows a typical error of ±30.3%, with 60% 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 →
20262.61.83.3
20272.61.93.3
20282.71.93.4
20292.72.03.4
20302.72.03.5

Blue-headed Vireo Survey Routes in Pennsylvania

Routes recording Blue-headed Vireo 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 →
Marsh Hill1620251983
Lynch1420251977
Roulette1220211972
Ridgway1120181988
Rasselas1120221981
Pottersdale920251968
Mawr Glen920251982
Eldred820221987
English Ctr819881987
Margaret820051992
Roulette 2720252022
Ltl Pine Cr720251990
Rothrock Sf720191993
Russell City620251968
Ryde620051995
Susquehanna520251971
Mill Run520241987
N Pine Grove420251970
Betula420221987
Laurel Hill420251979
Ansonia420252002
Sproul Sf-A420252002
Odin320251973
Arnot320251993
Munson320251979

Blue-headed Vireo Population Trend in Other States

alabamaconnecticutgeorgiakentuckymainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiorhode-islandsouth-carolinatennesseevermontvirginiawest-virginiawisconsin

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