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

Rose-breasted Grosbeak Population Trend in Iowa

All statesGeneralists

Rose-breasted Grosbeak in Iowa has edged up: up 12% on the route-weighted index since 1969.

+12%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 →
38Routes 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 Rose-breasted Grosbeak 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 Rose-breasted Grosbeak in Iowa. See the full index history below.

Rose-breasted Grosbeak Population Forecast in Iowa

If the recent trend holds, Rose-breasted Grosbeak in Iowa is projected to fall about 15% by 2029 — from 3.4 in 2024 to a central estimate of 2.9 (95% range 1.8–4.0). A 5-year backtest shows a typical error of ±18.4%, with 100% of held-out values landing inside the 95% band.

-15%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 →
2.9Projected 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 →
1.8–4.095% 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 →
±18.4%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, Rose-breasted Grosbeak in Iowa is projected to fall about 15% by 2029 — from 3.4 in 2024 to a central estimate of 2.9 (95% range 1.8–4.0). A 5-year backtest shows a typical error of ±18.4%, 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 →
20252.91.74.0
20262.91.84.0
20272.91.84.0
20282.91.84.0
20292.91.84.0

Rose-breasted Grosbeak Survey Routes in Iowa

Routes recording Rose-breasted Grosbeak 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 →
Red Rock1520241968
Mt Hamill1220241967
Panther1020241967
Mccallsburg920241996
Alice819991968
College Spgs 2820232005
Melrose620241974
Brooklyn620221967
Hudson620221967
Maquoketa520241968
Pierson520181968
Washta520141967
Exline420241974
West Liberty420241969
Bedford320181968
College Spgs320031967
Bryant220241967
Desmoines219781968
Wales220181967
Prairieburg220171968
Kanawha220161989
Zearing219951968
Rock Valley220191972
Tipton220241993
Lafayette220242003

Rose-breasted Grosbeak Population Trend in Other States

arkansasconnecticutgeorgiaillinoisindianakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-dakotatennesseevermontvirginiawest-virginiawisconsinwyoming

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