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

Green Heron Population Trend in Tennessee

All statesWetland birds

Green Heron in Tennessee has fallen sharply: down 75% on the route-weighted index since 1968.

-75%Since 1968TrendPercent 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 →
49Routes 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 →
58YearsYears 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 TennesseeNotable 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 Tennessee: down 75% on the route-weighted index since 1968.

Green Heron Population Forecast in Tennessee

If the recent trend holds, Green Heron in Tennessee is projected to fall about 21% by 2029 — from 0.36 in 2024 to a central estimate of 0.29 (95% range 0.00–0.74). A 5-year backtest shows a typical error of ±51.7%, 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 →
0.29Projected 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 →
0.00–0.7495% 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 →
±51.7%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, Green Heron in Tennessee is projected to fall about 21% by 2029 — from 0.36 in 2024 to a central estimate of 0.29 (95% range 0.00–0.74). A 5-year backtest shows a typical error of ±51.7%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.370.000.82
20260.350.000.80
20270.330.000.78
20280.310.000.76
20290.290.000.74

Green Heron Survey Routes in Tennessee

Routes recording Green Heron in Tennessee.
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 →
Peytonsville420211966
Big Sandy320221966
Campbellsville320171971
Corryton Rd320191967
Indian Mound 2320132004
Pawpaw220121969
Sweetlips220041966
Silerton220241967
Humboldt220241966
Wrigley220211966
Red Bank219781969
Lovell220191966
Jefferson Cty220061966
Allens Brdge220211966
Pawpaw 2220182013
Trace Collinwood220152015
Jones Gap220191986
Signal Mtn120181979
Tiptonville120161970
Moscow120231966
Brownsville120231966
Tibbs120211968
Whiteville120221966
Mansfield120241971
Trenton120211967

Green Heron Population Trend in Other States

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

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