BirdAnalyst
Species · Iowa · BBS 2026 Release · 1966–2025

Lark Sparrow Population Trend in Iowa

All statesGrassland birds

Lark Sparrow in Iowa has surged: up 160% on the route-weighted index since 1969.

+160%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 →
54YearsYears 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 160% 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 58% by 2030 — from 0.58 in 2025 to a central estimate of 0.92 (95% range 0.27–1.6). A 5-year backtest shows a typical error of ±65.8%, with 100% of held-out values landing inside the 95% band.

+58%Change by 2030TrendPercent 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 →
0.92Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.27–1.695% 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 →
±65.8%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, Lark Sparrow in Iowa is projected to rise about 58% by 2030 — from 0.58 in 2025 to a central estimate of 0.92 (95% range 0.27–1.6). A 5-year backtest shows a typical error of ±65.8%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20260.860.211.5
20270.880.231.5
20280.890.241.5
20290.900.261.6
20300.920.271.6

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 →
Wales420251979
Prairieburg419801980
Clare420191990
Mt Hamill320251967
Hudson320222009
College Spgs220041969
Cedar Valley219911986
Washington220222000
Neola220101969
Pierson220251985
Washta220251967
Sioux City220241984
Mccallsburg220252015
Exline120241974
Burchinal120252023
Bedford119891987
Bryant120252022
West Liberty120241970
Brooklyn120112007
Williamsburg120041969
Red Rock120251972
Panther120242008
Maquoketa120151971
Alice119771967
Dinsdale120131990

Lark Sparrow Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoidahoillinoisindianakansaskentuckylouisianaminnesotamississippimissourimontananebraskanevadanew-mexiconorth-dakotaohiooklahomaoregonsouth-dakotatennesseetexasutahwashingtonwisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.