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

Red-eyed Vireo Population Trend in Delaware

All statesForest birds

Red-eyed Vireo in Delaware has risen sharply: up 58% on the route-weighted index since 1968.

+58%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 →
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 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 58% 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 stay roughly flat through 2029, near 13 (95% range 6.9–20). A 5-year backtest shows a typical error of ±18.6%, with 100% of held-out values landing inside the 95% band.

+8%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 →
13Projected 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 →
6.9–2095% 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 →
±18.6%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 →
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 →
2025136.619
2026136.719
2027136.819
2028136.819
2029136.920

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 25620172017
Holleyville1920041966
Pepperbox 21620242017
Pepperbox1520161998
Millsboro1320242017
Blackbird1220241994
Harrington1120241966
Milton1120161966
Georgetown1120221992
Frederica1020141966
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 2026-05-22.