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

Great Blue Heron Population Trend in Vermont

All statesWetland birds

Great Blue Heron in Vermont has edged up: up 15% on the route-weighted index since 1969.

+15%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 →
25Routes 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 Great Blue Heron Trends in VermontNotable 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 Great Blue Heron in Vermont. See the full index history below.

Great Blue Heron Population Forecast in Vermont

If the recent trend holds, Great Blue Heron in Vermont is projected to rise about 35% by 2029 — from 0.39 in 2024 to a central estimate of 0.53 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±68.6%, with 100% of held-out values landing inside the 95% band.

+35%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 →
0.53Projected 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 →
0.00–1.495% 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 →
±68.6%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 Vermont is projected to rise about 35% by 2029 — from 0.39 in 2024 to a central estimate of 0.53 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±68.6%, 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 →
20250.530.001.4
20260.530.001.4
20270.530.001.4
20280.530.001.4
20290.530.001.4

Great Blue Heron Survey Routes in Vermont

Routes recording Great Blue Heron in Vermont.
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 →
S Reading320191991
Fletcher320241970
Waterville319791967
Landgrove220171968
St Johnsbury220231988
Hardwick220111970
Marlboro119951995
North Pownal120222017
Stratton120242019
Gaysville119881988
Post Mills120242009
Shaftsbury120231997
S Wallingfrd120221982
W Rutland120241973
East Haven120211968
Northfld Fls120172005
Middlesex120151974
East Calais120031968
Newbury119921986
Greensboro120221969
Hinesburg119941969
Colchester120231994
Grand Isle120241967
Stowe120012000
Bristol120091995

Great Blue Heron Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvirginiawashingtonwest-virginiawisconsinwyoming

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