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

Great Blue Heron Population Trend in Missouri

All statesWetland birds

Great Blue Heron in Missouri has surged: up 188% on the route-weighted index since 1970.

+188%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 →
90Routes 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 →
56YearsYears 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 MissouriNotable 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 Missouri: up 188% on the route-weighted index since 1970.

Great Blue Heron Population Forecast in Missouri

If the recent trend holds, Great Blue Heron in Missouri is projected to rise about 139% by 2029 — from 0.73 in 2024 to a central estimate of 1.7 (95% range 0.67–2.8). A 5-year backtest shows a typical error of ±72.5%, with 80% of held-out values landing inside the 95% band.

+139%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 →
1.7Projected 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 →
0.67–2.895% 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 →
±72.5%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 Missouri is projected to rise about 139% by 2029 — from 0.73 in 2024 to a central estimate of 1.7 (95% range 0.67–2.8). A 5-year backtest shows a typical error of ±72.5%, with 80% 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 →
20251.70.602.8
20261.70.622.8
20271.70.632.8
20281.70.652.8
20291.70.672.8

Great Blue Heron Survey Routes in Missouri

Routes recording Great Blue Heron in Missouri.
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 →
Stet819951981
Harrisonville720232017
Cascade620231988
Hayti620212021
Pulaski520211980
Filley520241975
Mcfall520231994
Deventer420231970
Cp Girardeau420241984
Kingsville420221992
Watson420231991
Clementine319961975
Kahoka319951967
Hilda320061999
Kearney320241994
Graniteville320232003
Peace Valley220221977
Sweden220241970
Pineville220231975
Handley220231968
Reeds220231975
Cole Camp219891982
Ohio220241973
Sni Mills219901977
Warren219751975

Great Blue Heron Population Trend in Other States

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

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