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

Black-throated Gray Warbler In Sierra Nevada

All regionsSierra NevadaForest birds

Black-throated Gray Warbler in Sierra Nevada has surged: up 311% on the route-weighted index since 1971.

+311%Since 1971TrendPercent 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 →
30Routes 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 →
55YearsYears 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 →

Black-throated Gray Warbler has surged in Sierra Nevada: up 311% on the route-weighted index since 1971.

Black-throated Gray Warbler In Sierra Nevada Population Forecast

If the recent trend holds, Black-throated Gray Warbler in Sierra Nevada is projected to rise about 68% by 2029 — from 3.2 in 2024 to a central estimate of 5.4 (95% range 3.0–7.9). A 5-year backtest shows a typical error of ±30.7%, with 100% of held-out values landing inside the 95% band.

+68%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 →
5.4Projected 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 →
3.0–7.995% 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 →
±30.7%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, Black-throated Gray Warbler in Sierra Nevada is projected to rise about 68% by 2029 — from 3.2 in 2024 to a central estimate of 5.4 (95% range 3.0–7.9). A 5-year backtest shows a typical error of ±30.7%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20255.22.87.7
20265.32.87.7
20275.32.97.8
20285.42.97.8
20295.43.07.9

Routes In Sierra Nevada

Routes recording Black-throated Gray Warbler 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 →
Forest HillCALIFORNIA392022
Forest Hill 2CALIFORNIA332005
PlacervilleCALIFORNIA222024
Silver CityCALIFORNIA112013
Butte MeadowCALIFORNIA112014
StrawberryCALIFORNIA102019
RivertonCALIFORNIA92023
GeneseeCALIFORNIA82024
LakeshoreCALIFORNIA62009
WestvilleCALIFORNIA52024
DardanelleCALIFORNIA52019
Tuolumne GroveCALIFORNIA52024
LumberyardCALIFORNIA42024
Higgins CornCALIFORNIA42024
DownievilleCALIFORNIA42024
SattleyCALIFORNIA31996
WawonaCALIFORNIA32024
Last ChanceCALIFORNIA32018
Bass LakeCALIFORNIA22018
Kings CanyonCALIFORNIA22024
PaxtonCALIFORNIA22024
Eagle LakeCALIFORNIA12024
Cottage SpgsCALIFORNIA11974
JohnsvilleCALIFORNIA12023
Greenhorn MtCALIFORNIA11988

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