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Species · Delaware · BBS 2026 Release · 1966–2025

Northern Bobwhite Population Trend in Delaware

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Northern Bobwhite in Delaware has collapsed: down 97% on the route-weighted index since 1968.

-97%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 →
14Routes 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 Northern Bobwhite 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 →

Northern Bobwhite has collapsed in Delaware: down 97% on the route-weighted index since 1968.

Northern Bobwhite Population Forecast in Delaware

If the recent trend holds, Northern Bobwhite in Delaware is projected to fall about 100% by 2030 — from 0.83 in 2025 to a central estimate of 0.00 (95% range 0.00–14). A 5-year backtest shows a typical error of ±883.7%, with 20% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–1495% 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 →
±883.7%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, Northern Bobwhite in Delaware is projected to fall about 100% by 2030 — from 0.83 in 2025 to a central estimate of 0.00 (95% range 0.00–14). A 5-year backtest shows a typical error of ±883.7%, with 20% 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 →
20260.000.0014
20270.000.0014
20280.000.0014
20290.000.0014
20300.000.0014

Northern Bobwhite Survey Routes in Delaware

Routes recording Northern Bobwhite 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 →
Dover1719871966
Lowes Xrds1719911966
Bethany Bch819901966
Blackbird520251994
Pepperbox420081998
Frederica320091966
Wilmington220131966
Holleyville220041966
Mt Pleasant120131966
Harrington120181966
Frankford120121966
Milton120141966
Holleyville 2120192006
Georgetown120221992

Northern Bobwhite Population Trend in Other States

alabamaarkansascoloradoconnecticutfloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawashingtonwest-virginiawisconsinwyoming

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