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

Northern Bobwhite Population Trend in Iowa

All statesGrassland birds

Northern Bobwhite in Iowa has fallen sharply: down 68% on the route-weighted index since 1969.

-68%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 →
57YearsYears 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 68% 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 rise about 58% by 2029 — from 1.7 in 2024 to a central estimate of 2.7 (95% range 0.00–8.7). A 5-year backtest shows a typical error of ±46%, with 100% of held-out values landing inside the 95% band.

+58%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 →
2.7Projected 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 →
0.00–8.795% 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 →
±46%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 rise about 58% by 2029 — from 1.7 in 2024 to a central estimate of 2.7 (95% range 0.00–8.7). A 5-year backtest shows a typical error of ±46%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20253.20.009.2
20263.10.009.1
20273.00.009.0
20282.80.008.9
20292.70.008.7

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 →
Bedford7920181968
Wales7920181967
College Spgs 25120232005
College Spgs3420041967
Mt Hamill1520241967
Exline1420241974
Cedar Valley1419971967
Melrose920231974
Clare719901975
Neola320161968
Prairieburg320001967
Hudson320061974
Washta320141967
Sioux City320241968
Garner319741974
Brooklyn220211968
Williamsburg220231967
Red Rock220241968
Dinsdale219921969
Scranton220241976
Pierson220131973
Bryant120181967
West Liberty120231968
Desmoines119791968
Panther120241967

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 2026-05-22.