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

Great Blue Heron Population Trend in Iowa

All statesWetland birds

Great Blue Heron in Iowa has surged: up 515% on the route-weighted index since 1970.

+515%Since 1970
38Routes In State
56Years

Notable Great Blue Heron Trends in Iowa

long arc increasecomputed index

Great Blue Heron has surged in Iowa: up 515% on the route-weighted index since 1970.

Great Blue Heron Population Forecast in Iowa

If the recent trend holds, Great Blue Heron in Iowa is projected to rise about 165% by 2029 — from 0.46 in 2024 to a central estimate of 1.2 (95% range 0.57–1.8). A 5-year backtest shows a typical error of ±147.9%, with 20% of held-out values landing inside the 95% band.

+165%Change by 2029
1.2Projected 2029 index
0.57–1.895% range
±147.9%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
20251.10.501.8
20261.20.521.8
20271.20.541.8
20281.20.551.8
20291.20.571.8

Great Blue Heron Survey Routes in Iowa

Routes recording Great Blue Heron in Iowa.
Mccallsburg420141997
Bedford320181986
Desmoines319781978
Panther320181994
Zearing319951989
Gaza320221976
Cedar Valley219891971
Red Rock220241988
Washington220231980
Neola220161992
Maquoketa220141974
Kanawha220241990
Sioux City220241977
Mt Hamill120231985
Exline120231974
Melrose120241974
College Spgs120042003
Bryant120171970
West Liberty120241983
Brooklyn120171998
Williamsburg120231991
Wales120172002
Alice119971988
Prairieburg120171982
Hudson120221969

Great Blue Heron Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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