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Species · Iowa · BBS 2025 Release · 1966–2024

Western Kingbird Population Trend in Iowa

All statesAerial insectivores

Western Kingbird in Iowa has fallen sharply: down 72% on the route-weighted index since 1969.

-72%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 →
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 →
49YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Western Kingbird 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 →

Western Kingbird has fallen sharply in Iowa: down 72% on the route-weighted index since 1969.

Western Kingbird Population Forecast in Iowa

If the recent trend holds, Western Kingbird in Iowa is projected to fall about 85% by 2028 — from 0.18 in 2023 to a central estimate of 0.03 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±42.8%, with 100% of held-out values landing inside the 95% band.

-85%Change by 2028TrendPercent 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 →
0.03Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.2795% 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 →
±42.8%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, Western Kingbird in Iowa is projected to fall about 85% by 2028 — from 0.18 in 2023 to a central estimate of 0.03 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±42.8%, with 100% of held-out values landing inside the 95% band.19672028
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 →
20240.050.000.28
20250.040.000.28
20260.040.000.27
20270.030.000.27
20280.030.000.27

Western Kingbird Survey Routes in Iowa

Routes recording Western Kingbird 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 →
Pierson720091970
Washta420121967
Sioux City420231968
Wales220001969
Gaza120021973
Rock Valley120011968
College Spgs119921967
College Spgs 2120132013
Williamsburg119891989
Washington119901990
Neola120001968
Prairieburg119981998
Scranton119921992
Davis Corner119841984

Western Kingbird Population Trend in Other States

alaskaarizonaarkansascaliforniacoloradoidahoillinoisindianakansaslouisianamichiganminnesotamississippimissourimontananebraskanevadanew-mexiconorth-dakotaoklahomaoregonsouth-dakotatennesseetexasutahwashingtonwisconsinwyoming

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