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

MacGillivray's Warbler In Sierra Nevada

All regionsSierra NevadaForest birds

MacGillivray's Warbler in Sierra Nevada has held roughly steady: down 8% on the route-weighted index since 1972.

-8%Since 1972TrendPercent 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 →
36Routes 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 →
54YearsYears 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 MacGillivray's Warbler in Sierra Nevada. See the full index history below.

MacGillivray's Warbler In Sierra Nevada Population Forecast

If the recent trend holds, MacGillivray's Warbler in Sierra Nevada is projected to rise about 100% by 2029 — from 2.4 in 2024 to a central estimate of 4.7 (95% range 2.7–6.7). A 5-year backtest shows a typical error of ±42.8%, with 60% of held-out values landing inside the 95% band.

+100%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 →
4.7Projected 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 →
2.7–6.795% 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 →
±42.8%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, MacGillivray's Warbler in Sierra Nevada is projected to rise about 100% by 2029 — from 2.4 in 2024 to a central estimate of 4.7 (95% range 2.7–6.7). A 5-year backtest shows a typical error of ±42.8%, with 60% of held-out values landing inside the 95% band.19682029
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 →
20254.62.66.6
20264.62.66.7
20274.72.76.7
20284.72.76.7
20294.72.76.7

Routes In Sierra Nevada

Routes recording MacGillivray's 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 →
Cottage SpgsCALIFORNIA171975
Tuolumne GroveCALIFORNIA112024
LakeshoreCALIFORNIA112024
DardanelleCALIFORNIA92019
RivertonCALIFORNIA92023
StrawberryCALIFORNIA92019
Eagle LakeCALIFORNIA62024
Greenhorn MtCALIFORNIA62008
Butte MeadowCALIFORNIA62014
Little TruckeeCALIFORNIA62022
ChesterCALIFORNIA52017
Last ChanceCALIFORNIA42019
Silver CityCALIFORNIA32013
Higgins CornCALIFORNIA31982
Tahoe NfCALIFORNIA31994
WawonaCALIFORNIA32024
Forest Hill 2CALIFORNIA32005
WestvilleCALIFORNIA22024
JohnsvilleCALIFORNIA22024
Forest HillCALIFORNIA22022
PlacervilleCALIFORNIA22024
Pine MountainCALIFORNIA22017
Bass LakeCALIFORNIA12011
WoodfordsCALIFORNIA12024
LumberyardCALIFORNIA12024

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