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

Turkey Vulture Population Trend in Iowa

All statesGeneralists

Turkey Vulture in Iowa has surged: up 14× on the route-weighted index since 1969.

14×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 →
35Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Turkey Vulture 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 increasecomputed 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 →

Turkey Vulture has surged in Iowa: up 14× on the route-weighted index since 1969.

Turkey Vulture Population Forecast in Iowa

If the recent trend holds, Turkey Vulture in Iowa is projected to stay roughly flat through 2029, near 4.0 (95% range 2.1–5.9). A 5-year backtest shows a typical error of ±32.2%, with 100% of held-out values landing inside the 95% band.

-7%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 →
4.0Projected 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 →
2.1–5.995% 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 →
±32.2%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, Turkey Vulture in Iowa is projected to stay roughly flat through 2029, near 4.0 (95% range 2.1–5.9). A 5-year backtest shows a typical error of ±32.2%, 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 →
20253.71.85.6
20263.81.85.7
20273.81.95.8
20283.92.05.9
20294.02.15.9

Turkey Vulture Survey Routes in Iowa

Routes recording Turkey Vulture 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 →
Bedford5420181981
Mt Hamill2120241967
Red Rock2020241969
Exline1620241990
Mccallsburg1020241996
Hudson620221986
Scranton620242007
Williamsburg520231992
Festina520241993
Dinsdale420241982
Washington320241996
Wales320181999
Zearing319951994
Clare320132001
Washta320141986
West Liberty220231994
Brooklyn220182003
Desmoines219701968
Alice219951978
Prairieburg220182012
Sioux City220222007
Davis Corner220242005
Tipton220242010
Melrose120241974
College Spgs120041971

Turkey Vulture Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.