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

Northern Bobwhite Population Trend in Iowa

All statesGame birds

Northern Bobwhite in Iowa has fallen sharply: down 58% on the route-weighted index since 1969.

-58%Since 1969TrendPercent 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 →
34Routes 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 IowaNotable 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 fallen sharply in Iowa: down 58% on the route-weighted index since 1969.

Northern Bobwhite Population Forecast in Iowa

If the recent trend holds, Northern Bobwhite in Iowa is projected to fall about 57% by 2030 — from 6.6 in 2025 to a central estimate of 2.9 (95% range 0.00–8.9). A 5-year backtest shows a typical error of ±35.7%, with 100% of held-out values landing inside the 95% band.

-57%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 →
2.9Projected 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 →
0.00–8.995% 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 →
±35.7%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 Iowa is projected to fall about 57% by 2030 — from 6.6 in 2025 to a central estimate of 2.9 (95% range 0.00–8.9). A 5-year backtest shows a typical error of ±35.7%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20263.30.009.3
20273.20.009.2
20283.10.009.1
20293.00.009.0
20302.90.008.9

Northern Bobwhite Survey Routes in Iowa

Routes recording Northern Bobwhite in Iowa.
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 →
College Spgs 210420252005
College Spgs3420041967
Wales3420251967
Bedford2620251968
Neola1920251968
Cedar Valley1419971967
Clare719901975
Mt Hamill520251967
Melrose420251974
Exline320251974
Red Rock320251968
Prairieburg320001967
Hudson320061974
Sioux City320241968
Garner319741974
Brooklyn220251968
Williamsburg220231967
Dinsdale219921969
Scranton220251976
Bryant120181967
West Liberty120251968
Desmoines119791968
Panther120241967
Washington120141967
Maquoketa120241967

Northern Bobwhite Population Trend in Other States

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

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