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

Great Blue Heron Population Trend in Colorado

All statesWetland birds

Great Blue Heron in Colorado has surged: up 219% on the route-weighted index since 1973.

+219%Since 1973
98Routes In State
52Years

Notable Great Blue Heron Trends in Colorado

long arc increasecomputed index

Great Blue Heron has surged in Colorado: up 219% on the route-weighted index since 1973.

Great Blue Heron Population Forecast in Colorado

If the recent trend holds, Great Blue Heron in Colorado is projected to rise about 116% by 2029 — from 0.26 in 2024 to a central estimate of 0.56 (95% range 0.19–0.92). A 5-year backtest shows a typical error of ±117%, with 60% of held-out values landing inside the 95% band.

+116%Change by 2029
0.56Projected 2029 index
0.19–0.9295% range
±117%Backtest error
19712029
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
20250.530.170.90
20260.540.170.90
20270.540.180.91
20280.550.180.92
20290.560.190.92

Great Blue Heron Survey Routes in Colorado

Routes recording Great Blue Heron in Colorado.
Buford1120231972
Fleming920031992
Wildhorse L520001991
Cokedale520242007
Cochetopa Pass520222001
Gilpin420161999
Walden420191999
Cortez420071993
Stillwater Pass 2420162012
Hudson320241989
Browns Park320151995
Grover320131999
Haswell319991993
Neegrande320191995
Flagler320031997
Elbert320192000
Yampa220181971
Harmony220191974
Pinneo219931973
Aspen220241993
Cheesman Lk220161995
Moffat220232023
Lost Lake220052005
Castleton220241991
Doyleville220241988

Great Blue Heron Population Trend in Other States

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

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