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

Yellow-headed Blackbird Population Trend in Iowa

All statesGeneralists

Yellow-headed Blackbird in Iowa has declined: down 43% on the route-weighted index since 1970.

-43%Since 1970TrendPercent 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 →
18Routes 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Yellow-headed Blackbird 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 Yellow-headed Blackbird in Iowa. See the full index history below.

Yellow-headed Blackbird Population Forecast in Iowa

If the recent trend holds, Yellow-headed Blackbird in Iowa is projected to stay roughly flat through 2029, near 0.27 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±303.3%, with 100% of held-out values landing inside the 95% band.

-3%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 →
0.27Projected 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 →
0.00–1.295% 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 →
±303.3%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, Yellow-headed Blackbird in Iowa is projected to stay roughly flat through 2029, near 0.27 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±303.3%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.300.001.3
20260.290.001.3
20270.280.001.2
20280.270.001.2
20290.270.001.2

Yellow-headed Blackbird Survey Routes in Iowa

Routes recording Yellow-headed Blackbird 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 →
Garner1819921971
Pierson620141993
Panther320241987
Hudson320091968
Kanawha320242019
Bryant220182018
Washington220091977
Sioux City220221969
Titonka120131983
Gaza120031977
Rock Valley119811971
Burchinal120232009
Brooklyn120122012
Williamsburg119971990
Scranton120171973
Washta119791979
Festina119841971
Davis Corner119891978

Yellow-headed Blackbird Population Trend in Other States

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