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Species · Maine · BBS 2025 Release · 1966–2024

Philadelphia Vireo Population Trend in Maine

All statesForest birds

Philadelphia Vireo in Maine has surged: up 109% on the route-weighted index since 1972.

+109%Since 1972TrendPercent 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 →
44Routes 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 →
49YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Philadelphia Vireo Trends in MaineNotable 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 →

Philadelphia Vireo has surged in Maine: up 109% on the route-weighted index since 1972.

Philadelphia Vireo Population Forecast in Maine

If the recent trend holds, Philadelphia Vireo in Maine is projected to rise about 87% by 2027 — from 0.29 in 2022 to a central estimate of 0.54 (95% range 0.17–0.90). A 5-year backtest shows a typical error of ±68.3%, with 100% of held-out values landing inside the 95% band.

+87%Change by 2027TrendPercent 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 →
0.54Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.17–0.9095% 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 →
±68.3%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, Philadelphia Vireo in Maine is projected to rise about 87% by 2027 — from 0.29 in 2022 to a central estimate of 0.54 (95% range 0.17–0.90). A 5-year backtest shows a typical error of ±68.3%, with 100% of held-out values landing inside the 95% band.19682027
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 →
20230.510.150.87
20240.520.150.88
20250.520.160.88
20260.530.170.89
20270.540.170.90

Philadelphia Vireo Survey Routes in Maine

Routes recording Philadelphia Vireo in Maine.
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 →
Ashland1120081988
Washburn919931989
Bethel620211978
Northfield 2520222018
Heron Lake520031986
Charleston520191975
Big Twenty520071993
Baker Lake519941994
Aurora420102009
Clayton Lake420011994
Moose River320051988
Forest Sta319851974
Nesowadnehun220211993
East Troy220192018
Brooks220182018
Medway219941976
Hudson220091982
Ludlow219831968
Yankeetuladi220091994
Biddeford120062006
Wilson Mills120121983
Greenwood120162016
Reeds120221990
South Arm120141983
Otisfield Gr120092003

Philadelphia Vireo Population Trend in Other States

alabamamichiganminnesotanew-hampshirenew-yorknorth-dakotavermontwisconsin

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