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

Red-eyed Vireo Population Trend in Illinois

All statesForest birds

Red-eyed Vireo in Illinois has surged: up 131% on the route-weighted index since 1968.

+131%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 →
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 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 131% 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 stay roughly flat through 2029, near 1.3 (95% range 0.70–1.8). A 5-year backtest shows a typical error of ±32.6%, with 40% of held-out values landing inside the 95% band.

+2%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 →
1.3Projected 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 →
0.70–1.895% 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 →
±32.6%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 stay roughly flat through 2029, near 1.3 (95% range 0.70–1.8). A 5-year backtest shows a typical error of ±32.6%, with 40% 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 →
20251.20.651.8
20261.20.661.8
20271.20.681.8
20281.20.691.8
20291.30.701.8

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
Belleview1120241966
Delwood820241970
Cave In Rock720241993
Athens720241996
Mascoutah Lk620241975
Bremen620241971
York620241993
Itasca420241968
Pulaski420241970
Wayne320231967
Chandlervill320241973
Melrose319991973
Pawnee320241967
Janesville320221981
Bradbury320241971
Beaverdam Lk320231970
Caledonia320231994
Alden320232019
Lake Summerset320222003
Union320172001
New Lenox220191967
Gulfport220232003
Bartonville220241976
Dailey220221973

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 2026-05-22.