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

Eastern Towhee Population Trend in Iowa

All statesGeneralists

Eastern Towhee in Iowa has surged: up 103% on the route-weighted index since 1969.

+103%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 →
30Routes 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 Eastern Towhee 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 →

Eastern Towhee has surged in Iowa: up 103% on the route-weighted index since 1969.

Eastern Towhee Population Forecast in Iowa

If the recent trend holds, Eastern Towhee in Iowa is projected to rise about 10% by 2029 — from 0.95 in 2024 to a central estimate of 1.1 (95% range 0.46–1.6). A 5-year backtest shows a typical error of ±51.3%, with 100% of held-out values landing inside the 95% band.

+10%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 →
1.1Projected 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 →
0.46–1.695% 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 →
±51.3%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, Eastern Towhee in Iowa is projected to rise about 10% by 2029 — from 0.95 in 2024 to a central estimate of 1.1 (95% range 0.46–1.6). A 5-year backtest shows a typical error of ±51.3%, 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 →
20250.990.401.6
20261.00.411.6
20271.00.431.6
20281.00.451.6
20291.10.461.6

Eastern Towhee Survey Routes in Iowa

Routes recording Eastern Towhee 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 →
Exline920241975
Maquoketa520241968
Melrose420241977
Washta420141975
Bedford320181968
Wales320181967
Alice319971969
Brooklyn220131967
College Spgs 2220232010
Mt Hamill120231967
College Spgs119711967
Bryant120081971
West Liberty120241986
Cedar Valley119891967
Williamsburg120232008
Red Rock120241970
Washington120241967
Neola120161976
Prairieburg119821971
Hudson120122012
Dinsdale119911983
Scranton120182018
Clare120191985
Pierson120132001
Sioux City120181987

Eastern Towhee Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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