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

Blue Grosbeak Population Trend in Iowa

All statesGeneralists

Blue Grosbeak in Iowa has surged: up 344% on the route-weighted index since 1970.

+344%Since 1970
17Routes In State
55Years

Notable Blue Grosbeak Trends in Iowa

long arc increasecomputed index

Blue Grosbeak has surged in Iowa: up 344% on the route-weighted index since 1970.

Blue Grosbeak Population Forecast in Iowa

If the recent trend holds, Blue Grosbeak in Iowa is projected to rise about 65% by 2029 — from 0.50 in 2024 to a central estimate of 0.83 (95% range 0.26–1.4). A 5-year backtest shows a typical error of ±84.9%, with 80% of held-out values landing inside the 95% band.

+65%Change by 2029
0.83Projected 2029 index
0.26–1.495% range
±84.9%Backtest error
19682029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20250.790.221.3
20260.800.231.4
20270.810.241.4
20280.820.251.4
20290.830.261.4

Blue Grosbeak Survey Routes in Iowa

Routes recording Blue Grosbeak in Iowa.
Gaza720231970
College Spgs 2420222018
Mt Hamill320242008
Pierson320181968
Washta320141979
Sioux City320241973
Rock Valley220241968
Scranton220212021
Clare220192009
Exline120242015
Melrose120242024
College Spgs119711968
Bryant120232023
Williamsburg119941994
Mccallsburg120242019
Neola119811977
Wales120172013

Blue Grosbeak Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradodelawarefloridageorgiaidahoillinoisindianakansaskentuckylouisianamarylandminnesotamississippimissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvirginiawest-virginiawyoming

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