BirdAnalyst
Species · BCR 15 · BBS 2025 Release · 1966–2024

Great Blue Heron In Sierra Nevada

All regionsSierra NevadaWetland birds

Great Blue Heron in Sierra Nevada has edged down: down 15% on the route-weighted index since 1976.

-15%Since 1976TrendPercent 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 →
18Routes 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 →
35YearsYears 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 Sierra Nevada. See the full index history below.

Great Blue Heron In Sierra Nevada Population Forecast

If the recent trend holds, Great Blue Heron in Sierra Nevada is projected to fall about 35% by 2029 — from 0.16 in 2024 to a central estimate of 0.10 (95% range 0.00–0.25). A 5-year backtest shows a typical error of ±103.3%, with 100% of held-out values landing inside the 95% band.

-35%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 →
0.10Projected 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 →
0.00–0.2595% 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 →
±103.3%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 Sierra Nevada is projected to fall about 35% by 2029 — from 0.16 in 2024 to a central estimate of 0.10 (95% range 0.00–0.25). A 5-year backtest shows a typical error of ±103.3%, with 100% of held-out values landing inside the 95% band.19732029
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 →
20250.100.000.25
20260.100.000.25
20270.100.000.25
20280.100.000.25
20290.100.000.25

Routes In Sierra Nevada

Routes recording Great Blue Heron in Sierra Nevada.
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 →
Bass LakeCALIFORNIA42009
SattleyCALIFORNIA21992
Butte MeadowCALIFORNIA21995
LakeshoreCALIFORNIA22009
PaxtonCALIFORNIA22024
Eagle LakeCALIFORNIA12006
JohnsvilleCALIFORNIA11990
LumberyardCALIFORNIA12019
Silver CityCALIFORNIA12010
Kings CanyonCALIFORNIA11987
Tuolumne GroveCALIFORNIA12016
GeneseeCALIFORNIA12013
Higgins CornCALIFORNIA12003
DownievilleCALIFORNIA11984
Hat CreekCALIFORNIA12007
Chaos CraterCALIFORNIA11993
CoultervilleCALIFORNIA12013
WawonaCALIFORNIA12024

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