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

Mallard Population Trend in Iowa

All statesWaterfowl

Mallard in Iowa has surged: up 195% on the route-weighted index since 1970.

+195%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 →
37Routes 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 Mallard 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 →

Mallard has surged in Iowa: up 194% on the route-weighted index since 1970.

Mallard Population Forecast in Iowa

If the recent trend holds, Mallard in Iowa is projected to rise about 21% by 2029 — from 1.4 in 2024 to a central estimate of 1.7 (95% range 0.34–3.1). A 5-year backtest shows a typical error of ±120.6%, with 80% of held-out values landing inside the 95% band.

+21%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 →
1.7Projected 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 →
0.34–3.195% 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 →
±120.6%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, Mallard in Iowa is projected to rise about 21% by 2029 — from 1.4 in 2024 to a central estimate of 1.7 (95% range 0.34–3.1). A 5-year backtest shows a typical error of ±120.6%, with 80% 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 →
20251.60.273.0
20261.60.293.0
20271.70.303.0
20281.70.323.0
20291.70.343.1

Mallard Survey Routes in Iowa

Routes recording Mallard 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 →
Exline920142004
Garner719931973
Washington620241980
Titonka620241974
Williamsburg520161984
Scranton520241973
Sioux City520241970
Washta419931984
Davis Corner320051987
Burchinal220241995
Cedar Valley219971978
Brooklyn220181974
Neola219991977
Wales220131993
Alice219991970
Dinsdale220131983
Kanawha220241973
Zearing219951984
Clare220191976
Pierson220181979
Festina220131969
Lafayette220132004
Mccallsburg220241996
Mt Hamill120152000
Melrose120221974

Mallard Population Trend in Other States

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

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