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

Green Heron Population Trend in Vermont

All statesWetland birds

Green Heron in Vermont has fallen sharply: down 72% on the route-weighted index since 1970.

-72%Since 1970TrendPercent 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 →
20Routes 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 →
45YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Green 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 →

long arc declinecomputed 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 →

Green Heron has fallen sharply in Vermont: down 72% on the route-weighted index since 1970.

Green Heron Population Forecast in Vermont

If the recent trend holds, Green Heron in Vermont is projected to stay roughly flat through 2028, near 0.05 (95% range 0.00–0.23). A 5-year backtest shows a typical error of ±47%, with 100% of held-out values landing inside the 95% band.

-4%Change by 2028TrendPercent 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 →
0.05Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.2395% 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 →
±47%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, Green Heron in Vermont is projected to stay roughly flat through 2028, near 0.05 (95% range 0.00–0.23). A 5-year backtest shows a typical error of ±47%, with 100% of held-out values landing inside the 95% band.19662028
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 →
20240.070.000.24
20250.060.000.23
20260.060.000.23
20270.060.000.23
20280.050.000.23

Green Heron Survey Routes in Vermont

Routes recording Green 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 →
W Rutland220151972
Hinesburg219941971
North Pownal120211981
Landgrove119831970
S Reading119981966
Gaysville119961966
Post Mills120231983
Shaftsbury119751975
S Wallingfrd120101967
St Johnsbury119951972
East Haven119951971
Middlesex119851985
Hardwick119891970
Greensboro120071972
Fletcher120191971
Waterville119701967
Colchester120211987
Grand Isle120161973
Stowe119891989
Bristol119981998

Green Heron Population Trend in Other States

alabamaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvirginiawashingtonwest-virginiawisconsin

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