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

Yellow-throated Vireo Population Trend in Delaware

All statesForest birds

Yellow-throated Vireo in Delaware has fallen sharply: down 61% on the route-weighted index since 1968.

-61%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 →
16Routes 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 →
46YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Yellow-throated 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 declinecomputed 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 →

Yellow-throated Vireo has fallen sharply in Delaware: down 61% on the route-weighted index since 1968.

Yellow-throated Vireo Population Forecast in Delaware

If the recent trend holds, Yellow-throated Vireo in Delaware is projected to stay roughly flat through 2030, near 0.17 (95% range 0.00–0.63). A 5-year backtest shows a typical error of ±30.2%, with 100% of held-out values landing inside the 95% band.

-1%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 →
0.17Projected 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 →
0.00–0.6395% 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 →
±30.2%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, Yellow-throated Vireo in Delaware is projected to stay roughly flat through 2030, near 0.17 (95% range 0.00–0.63). A 5-year backtest shows a typical error of ±30.2%, with 100% 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 →
20260.180.000.65
20270.180.000.64
20280.170.000.64
20290.170.000.63
20300.170.000.63

Yellow-throated Vireo Survey Routes in Delaware

Routes recording Yellow-throated 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 →
Frankford519911966
Holleyville220031966
Mt Pleasant119991967
Wilmington119791970
Harrington120171966
Frederica119801971
Dover119791979
Lowes Xrds119771968
Bethany Bch119841967
Milton120021968
Blackbird120232017
Millsboro120252025
Pepperbox120062006
Georgetown120181992
Milton 2120172017
Pepperbox 2120212019

Yellow-throated Vireo Population Trend in Other States

alabamaarkansasconnecticutfloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsin

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