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

Red-eyed Vireo Population Trend in Illinois

All statesForest birds

Red-eyed Vireo in Illinois has surged: up 124% on the route-weighted index since 1968.

+124%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 →
104Routes 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 Red-eyed Vireo Trends in IllinoisNotable 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 →

Red-eyed Vireo has surged in Illinois: up 124% on the route-weighted index since 1968.

Red-eyed Vireo Population Forecast in Illinois

If the recent trend holds, Red-eyed Vireo in Illinois is projected to fall about 15% by 2030 — from 1.5 in 2025 to a central estimate of 1.3 (95% range 0.74–1.9). A 5-year backtest shows a typical error of ±34.7%, 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 →
1.3Projected 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 →
0.74–1.995% 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 →
±34.7%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, Red-eyed Vireo in Illinois is projected to fall about 15% by 2030 — from 1.5 in 2025 to a central estimate of 1.3 (95% range 0.74–1.9). A 5-year backtest shows a typical error of ±34.7%, 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 →
20261.20.691.8
20271.30.701.8
20281.30.711.8
20291.30.721.8
20301.30.741.9

Red-eyed Vireo Survey Routes in Illinois

Routes recording Red-eyed Vireo in Illinois.
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 →
Sandusky2420231993
Belleview1420251966
Delwood820251970
Bremen720251971
York720251993
Cave In Rock720241993
Eubanks620252001
Belknap520251974
Terre Haute420251971
Bradbury420251971
Itasca320251968
Stillwell320251992
Chandlervill320251973
Melrose319991973
Pawnee320241967
Janesville320221981
Columbia320251970
Mascoutah Lk320251975
Beaverdam Lk320231970
Caledonia320231994
Duncan Mills320252012
Eldred320251993
Union320172001
Royalton320252001
Athens320251996

Red-eyed Vireo Population Trend in Other States

alabamaalaskaarkansascoloradoconnecticutdelawarefloridageorgiaidahoindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawashingtonwest-virginiawisconsinwyoming

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