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

Yellow-throated Vireo Population Trend in Delaware

All statesForest birds

Yellow-throated Vireo in Delaware has fallen sharply: down 62% on the route-weighted index since 1968.

-62%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 →
15Routes 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 →
45YearsYears 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 62% 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 fall about 25% by 2028 — from 0.25 in 2023 to a central estimate of 0.19 (95% range 0.00–0.67). A 5-year backtest shows a typical error of ±31.7%, with 80% of held-out values landing inside the 95% band.

-25%Change by 2028TrendPercent 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 →
0.19Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.6795% 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 →
±31.7%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, Yellow-throated Vireo in Delaware is projected to fall about 25% by 2028 — from 0.25 in 2023 to a central estimate of 0.19 (95% range 0.00–0.67). A 5-year backtest shows a typical error of ±31.7%, with 80% of held-out values landing inside the 95% band.19662028
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 →
20240.200.000.68
20250.200.000.68
20260.200.000.67
20270.190.000.67
20280.190.000.67

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
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 2026-05-22.