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

Blue-gray Gnatcatcher In Sierra Nevada

All regionsSierra NevadaForest birds

Blue-gray Gnatcatcher in Sierra Nevada has held roughly steady: up 5% on the route-weighted index since 1974.

+5%Since 1974TrendPercent 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 →
21Routes 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 →
47YearsYears 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 Blue-gray Gnatcatcher in Sierra Nevada. See the full index history below.

Blue-gray Gnatcatcher In Sierra Nevada Population Forecast

If the recent trend holds, Blue-gray Gnatcatcher in Sierra Nevada is projected to rise about 225% by 2029 — from 0.32 in 2024 to a central estimate of 1.0 (95% range 0.23–1.8). A 5-year backtest shows a typical error of ±207.8%, with 40% of held-out values landing inside the 95% band.

+225%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 →
1.0Projected 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 →
0.23–1.895% 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 →
±207.8%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, Blue-gray Gnatcatcher in Sierra Nevada is projected to rise about 225% by 2029 — from 0.32 in 2024 to a central estimate of 1.0 (95% range 0.23–1.8). A 5-year backtest shows a typical error of ±207.8%, with 40% of held-out values landing inside the 95% band.19722029
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 →
20250.970.171.8
20260.980.181.8
20271.000.201.8
20281.00.211.8
20291.00.231.8

Routes In Sierra Nevada

Routes recording Blue-gray Gnatcatcher 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 →
Silver CityCALIFORNIA72013
CoultervilleCALIFORNIA72019
Forest HillCALIFORNIA42022
Tuolumne GroveCALIFORNIA32024
WestvilleCALIFORNIA22019
Cottage SpgsCALIFORNIA21973
Bass LakeCALIFORNIA22019
KernvilleCALIFORNIA22008
Forest Hill 2CALIFORNIA22005
Eagle LakeCALIFORNIA12022
WoodfordsCALIFORNIA11998
Greenhorn MtCALIFORNIA11973
Kings CanyonCALIFORNIA12024
Higgins CornCALIFORNIA12024
DownievilleCALIFORNIA11984
RivertonCALIFORNIA12021
LakeshoreCALIFORNIA12024
WawonaCALIFORNIA12023
Pine MountainCALIFORNIA12017
ChilcootCALIFORNIA12023
StrawberryCALIFORNIA12018

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