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

Blue-winged Teal Population Trend in Iowa

All statesWaterfowl

Blue-winged Teal in Iowa has increased: up 38% on the route-weighted index since 1969.

+38%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 →
26Routes 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 →
48YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Blue-winged Teal 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 →

No notable trend signals for Blue-winged Teal in Iowa. See the full index history below.

Blue-winged Teal Population Forecast in Iowa

If the recent trend holds, Blue-winged Teal in Iowa is projected to fall about 69% by 2029 — from 0.59 in 2024 to a central estimate of 0.18 (95% range 0.00–0.56). A 5-year backtest shows a typical error of ±86.5%, with 80% of held-out values landing inside the 95% band.

-69%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 →
0.18Projected 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 →
0.00–0.5695% 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 →
±86.5%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, Blue-winged Teal in Iowa is projected to fall about 69% by 2029 — from 0.59 in 2024 to a central estimate of 0.18 (95% range 0.00–0.56). A 5-year backtest shows a typical error of ±86.5%, with 80% 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 →
20250.190.000.56
20260.190.000.56
20270.180.000.56
20280.180.000.56
20290.180.000.56

Blue-winged Teal Survey Routes in Iowa

Routes recording Blue-winged Teal 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 →
Sioux City1320241970
Cedar Valley319731973
Desmoines319791968
Kanawha320232017
Rock Valley319881971
Burchinal220082008
Bryant219801969
Washington220221980
Alice219941994
Hudson219831973
Pierson219791976
Garner219931976
Melrose120121981
Bedford120172017
West Liberty119781978
Panther120132007
Neola119791979
Wales120131967
Dinsdale119871987
Zearing119931975
Scranton119981973
Clare119951982
Festina119931968
Titonka120161981
Gaza120031983

Blue-winged Teal Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradodelawarefloridaidahoillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-mexiconew-yorknorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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