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

Lark Sparrow Population Trend in Iowa

All statesGrassland birds

Lark Sparrow in Iowa has surged: up 197% on the route-weighted index since 1969.

+197%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 →
31Routes 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 →
53YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Lark Sparrow 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 →

Lark Sparrow has surged in Iowa: up 196% on the route-weighted index since 1969.

Lark Sparrow Population Forecast in Iowa

If the recent trend holds, Lark Sparrow in Iowa is projected to rise about 126% by 2029 — from 0.41 in 2024 to a central estimate of 0.93 (95% range 0.28–1.6). A 5-year backtest shows a typical error of ±58.1%, with 100% of held-out values landing inside the 95% band.

+126%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 →
0.93Projected 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 →
0.28–1.695% 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 →
±58.1%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, Lark Sparrow in Iowa is projected to rise about 126% by 2029 — from 0.41 in 2024 to a central estimate of 0.93 (95% range 0.28–1.6). A 5-year backtest shows a typical error of ±58.1%, 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 →
20250.870.221.5
20260.880.231.5
20270.900.251.5
20280.910.261.6
20290.930.281.6

Lark Sparrow Survey Routes in Iowa

Routes recording Lark Sparrow 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 →
Pierson920141985
Washta820141967
Prairieburg419801980
Clare420191990
College Spgs 2420232005
Hudson320222009
Mccallsburg320242015
Burchinal220232023
College Spgs220041969
Cedar Valley219911986
Red Rock220231972
Washington220222000
Neola220101969
Sioux City220241984
Mt Hamill120241967
Exline120241974
Bedford119891987
Bryant120222022
West Liberty120241970
Brooklyn120112007
Williamsburg120041969
Panther120242008
Wales120161979
Maquoketa120151971
Alice119771967

Lark Sparrow Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoidahoillinoisindianakansaskentuckylouisianaminnesotamississippimissourimontananebraskanevadanew-mexiconorth-dakotaohiooklahomaoregonsouth-dakotatennesseetexasutahwashingtonwisconsinwyoming

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