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

Savannah Sparrow Population Trend in Iowa

All statesGrassland birds

Savannah Sparrow in Iowa has declined: down 38% on the route-weighted index since 1969.

-38%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 →
32Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Savannah 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 →

No notable trend signals for Savannah Sparrow in Iowa. See the full index history below.

Savannah Sparrow Population Forecast in Iowa

If the recent trend holds, Savannah Sparrow in Iowa is projected to rise about 120% by 2029 — from 0.09 in 2024 to a central estimate of 0.20 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±311.8%, with 100% of held-out values landing inside the 95% band.

+120%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 →
0.20Projected 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 →
0.00–4.095% 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 →
±311.8%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, Savannah Sparrow in Iowa is projected to rise about 120% by 2029 — from 0.09 in 2024 to a central estimate of 0.20 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±311.8%, 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 →
20250.440.004.2
20260.380.004.2
20270.320.004.1
20280.260.004.1
20290.200.004.0

Savannah Sparrow Survey Routes in Iowa

Routes recording Savannah 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 →
Cedar Valley819971972
Burchinal620091995
Exline520061979
Pierson520121988
Brooklyn420131983
Garner419931973
Washington320231973
Titonka320051984
Gaza320131982
Maquoketa220191971
Prairieburg220151968
Hudson220221967
Dinsdale220131968
Washta220141990
Lafayette220152004
Mt Hamill120061976
Melrose119771977
College Spgs119911991
Bryant120241974
West Liberty120091975
Williamsburg120041971
Red Rock119971972
Panther120031974
Wales119911967
Alice119841977

Savannah Sparrow Population Trend in Other States

alaskaarizonacaliforniacoloradoconnecticutdelawareidahoillinoisindianakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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