BirdAnalyst
Species · BCR 11 · BBS 2026 Release · 1966–2025

Great Blue Heron In Prairie Potholes

All regionsPrairie PotholesWetland birds

Great Blue Heron in Prairie Potholes has surged: up 191% on the route-weighted index since 1969.

+191%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 →
106Routes In RegionSurvey 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 SignalsNotable 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 Prairie Potholes: up 191% on the route-weighted index since 1969.

Great Blue Heron In Prairie Potholes Population Forecast

If the recent trend holds, Great Blue Heron in Prairie Potholes is projected to rise about 119% by 2030 — from 0.36 in 2025 to a central estimate of 0.80 (95% range 0.16–1.4). A 5-year backtest shows a typical error of ±121%, with 100% of held-out values landing inside the 95% band.

+119%Change by 2030TrendPercent 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 →
0.80Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.16–1.495% 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 →
±121%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 Prairie Potholes is projected to rise about 119% by 2030 — from 0.36 in 2025 to a central estimate of 0.80 (95% range 0.16–1.4). A 5-year backtest shows a typical error of ±121%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20260.770.141.4
20270.780.141.4
20280.790.151.4
20290.790.161.4
20300.800.161.4

Routes In Prairie Potholes

Routes recording Great Blue Heron in Prairie Potholes.
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 →
ChinookMONTANA62022
Big StoneMINNESOTA52012
MccallsburgIOWA42014
OkleeMINNESOTA42014
RoswellSOUTH-DAKOTA42014
Lane 2SOUTH-DAKOTA42014
PantherIOWA32018
ZearingIOWA31995
Lake BronsonMINNESOTA32011
FairmontMINNESOTA32025
TracyMINNESOTA32025
GlasgowMONTANA32024
EmeradoNORTH-DAKOTA32023
GeddesSOUTH-DAKOTA32025
TurtonSOUTH-DAKOTA32024
WashingtonIOWA22023
KanawhaIOWA22024
ScrantonIOWA22025
MaynardMINNESOTA22000
DawsonMINNESOTA22019
GryglaMINNESOTA22017
BadgerMINNESOTA22012
WorthingtonMINNESOTA22024
TylerMINNESOTA22002
Great FallsMONTANA22016

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.