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

Summer Tanager Population Trend in Iowa

All statesForest birds

Summer Tanager in Iowa has declined: down 38% on the route-weighted index since 2005.

-38%Since 2005TrendPercent 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 →
6Routes 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 →
18YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Summer Tanager 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 Summer Tanager in Iowa. See the full index history below.

Summer Tanager Population Forecast in Iowa

If the recent trend holds, Summer Tanager in Iowa is projected to stay roughly flat through 2030, near 0.07 (95% range 0.01–0.14). A 5-year backtest shows a typical error of ±40.3%, with 60% of held-out values landing inside the 95% band.

n/aChange 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 →
0.07Projected 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 →
0.01–0.1495% 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 →
±40.3%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, Summer Tanager in Iowa is projected to stay roughly flat through 2030, near 0.07 (95% range 0.01–0.14). A 5-year backtest shows a typical error of ±40.3%, with 60% of held-out values landing inside the 95% band.20002030
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 →
20260.070.000.14
20270.070.000.14
20280.070.000.14
20290.070.000.14
20300.070.010.14

Summer Tanager Survey Routes in Iowa

Routes recording Summer Tanager 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 →
Wales220182018
Hudson220122012
Mt Hamill120252000
Exline120222003
Tipton120152015
Washington120142014

Summer Tanager Population Trend in Other States

alabamaarizonaarkansascaliforniadelawarefloridageorgiaillinoisindianakansaskentuckylouisianamarylandmississippimissourinebraskanevadanew-jerseynew-mexiconorth-carolinaohiooklahomapennsylvaniasouth-carolinatennesseetexasutahvirginiawest-virginiawisconsin

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