BirdAnalyst
Species · BCR 29 · BBS 2026 Release · 1966–2025

Great Blue Heron In Piedmont

All regionsPiedmontWetland birds

Great Blue Heron in Piedmont has surged: up 22× on the route-weighted index since 1970.

22×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 →
154Routes 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 →
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 SignalsNotable 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 Piedmont. See the full index history below.

Great Blue Heron In Piedmont Population Forecast

If the recent trend holds, Great Blue Heron in Piedmont is projected to rise about 54% by 2030 — from 0.79 in 2025 to a central estimate of 1.2 (95% range 0.73–1.7). A 5-year backtest shows a typical error of ±66.8%, with 20% of held-out values landing inside the 95% band.

+54%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 →
1.2Projected 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 →
0.73–1.795% 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 →
±66.8%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 Piedmont is projected to rise about 54% by 2030 — from 0.79 in 2025 to a central estimate of 1.2 (95% range 0.73–1.7). A 5-year backtest shows a typical error of ±66.8%, with 20% 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 →
20261.10.651.6
20271.20.671.6
20281.20.691.7
20291.20.711.7
20301.20.731.7

Routes In Piedmont

Routes recording Great Blue Heron in Piedmont.
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 →
HallVIRGINIA92023
BrodnaxVIRGINIA72025
Bald FriarMARYLAND51996
DurhamNORTH-CAROLINA52025
ChathamPENNSYLVANIA52025
LincolntonGEORGIA42013
RutledgeGEORGIA42025
Rock BranchGEORGIA42024
Upper XrdsMARYLAND42007
CrotonNEW-JERSEY42002
Mount AiryNORTH-CAROLINA42024
AkronPENNSYLVANIA41997
Mt Gretna 2PENNSYLVANIA42018
ShrewsburyPENNSYLVANIA42019
Sunny SideGEORGIA32017
HebronGEORGIA32019
PottersvilleNEW-JERSEY32023
WilgroveNORTH-CAROLINA32023
FlayNORTH-CAROLINA32023
BullockNORTH-CAROLINA32025
BendersvillePENNSYLVANIA32024
DavidVIRGINIA32013
Lake AnnaVIRGINIA32025
Nixburg 2ALABAMA22025
GrovetownGEORGIA22019

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