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

Red-eyed Vireo Population Trend in Delaware

All statesForest birds

Red-eyed Vireo in Delaware has risen sharply: up 66% on the route-weighted index since 1968.

+66%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 →
17Routes 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 DelawareNotable 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 risen sharply in Delaware: up 66% on the route-weighted index since 1968.

Red-eyed Vireo Population Forecast in Delaware

If the recent trend holds, Red-eyed Vireo in Delaware is projected to fall about 27% by 2030 — from 19 in 2025 to a central estimate of 14 (95% range 7.5–20). A 5-year backtest shows a typical error of ±17.7%, with 80% of held-out values landing inside the 95% band.

-27%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 →
14Projected 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 →
7.5–2095% 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 →
±17.7%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 Delaware is projected to fall about 27% by 2030 — from 19 in 2025 to a central estimate of 14 (95% range 7.5–20). A 5-year backtest shows a typical error of ±17.7%, with 80% 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 →
2026137.219
2027137.220
2028137.320
2029147.420
2030147.520

Red-eyed Vireo Survey Routes in Delaware

Routes recording Red-eyed Vireo in Delaware.
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 →
Milton 23520252017
Pepperbox 22120252017
Holleyville1920041966
Harrington1720251966
Blackbird1620251994
Pepperbox1520161998
Millsboro1220252017
Frederica1120251966
Milton1120161966
Georgetown1120221992
Frankford1020121966
Mt Pleasant920191966
Holleyville 2920242006
Wilmington620141966
Bethany Bch519901966
Dover419871966
Lowes Xrds219911966

Red-eyed Vireo Population Trend in Other States

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

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