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

Great Blue Heron Population Trend in Idaho

All statesWetland birds

Great Blue Heron in Idaho has surged: up 157% on the route-weighted index since 1972.

+157%Since 1972TrendPercent 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 →
41Routes 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 →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Great Blue Heron Trends in IdahoNotable 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 →

Great Blue Heron has surged in Idaho: up 157% on the route-weighted index since 1972.

Great Blue Heron Population Forecast in Idaho

If the recent trend holds, Great Blue Heron in Idaho is projected to fall about 21% by 2029 — from 0.56 in 2024 to a central estimate of 0.44 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±31.7%, with 100% of held-out values landing inside the 95% band.

-21%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 →
0.44Projected 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 →
0.00–1.195% 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 →
±31.7%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, Great Blue Heron in Idaho is projected to fall about 21% by 2029 — from 0.56 in 2024 to a central estimate of 0.44 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±31.7%, with 100% of held-out values landing inside the 95% band.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 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 →
20250.460.001.1
20260.460.001.1
20270.450.001.1
20280.450.001.1
20290.440.001.1

Great Blue Heron Survey Routes in Idaho

Routes recording Great Blue Heron in Idaho.
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 →
Baker820241974
Preston620231988
Craters419881982
Bates420191989
Pasadena Val420151987
Naples320241973
Cedar Hill320221989
Nezperce220071998
Tractor Flat219941994
Leadore220231975
Blacks Creek220171973
Pocatello220191997
Baldy Mountain220152015
Picabo220211989
Mud Lake220101993
Cabarton220231985
Blackft Res120131987
Mivoden120191977
Gifford120111986
Lolo Pass120162016
Cascade119841980
Cape Horn120222013
Challis120231982
Dubois120002000
Squirrel120231972

Great Blue Heron Population Trend in Other States

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

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