BirdAnalyst
Species · BCR 9 · BBS 2026 Release · 1966–2025

MacGillivray's Warbler In Great Basin

All regionsGreat BasinForest birds

MacGillivray's Warbler in Great Basin has increased: up 27% on the route-weighted index since 1970.

+27%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 →
109Routes 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 MacGillivray's Warbler in Great Basin. See the full index history below.

MacGillivray's Warbler In Great Basin Population Forecast

If the recent trend holds, MacGillivray's Warbler in Great Basin is projected to stay roughly flat through 2030, near 1.9 (95% range 1.2–2.7). A 5-year backtest shows a typical error of ±14.4%, with 100% of held-out values landing inside the 95% band.

+6%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 →
1.9Projected 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 →
1.2–2.795% 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 →
±14.4%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 Great Basin is projected to stay roughly flat through 2030, near 1.9 (95% range 1.2–2.7). A 5-year backtest shows a typical error of ±14.4%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20261.91.22.6
20271.91.22.6
20281.91.22.6
20291.91.22.6
20301.91.22.7

Routes In Great Basin

Routes recording MacGillivray's Warbler in Great Basin.
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 →
AustinNEVADA362018
E. Mt. AdamsWASHINGTON352025
Magic MtnIDAHO312025
Blewett PassWASHINGTON282025
GlacierWASHINGTON182024
SnowdenWASHINGTON172025
LeavenworthWASHINGTON152024
Mt HoodOREGON142025
NewhalemWASHINGTON142025
Picture FlatOREGON122025
RonaldWASHINGTON122025
White ChuckWASHINGTON112025
RimrockWASHINGTON102025
Ruby ValleyNEVADA92001
Wizard FallsOREGON92025
Cascade RivWASHINGTON92006
MazamaWASHINGTON82022
HawthorneNEVADA72001
KendallWASHINGTON72025
JarbidgeNEVADA62015
Comins LakeNEVADA62016
LakeviewOREGON62025
L. WenatcheeWASHINGTON62025
Lake ChelanWASHINGTON62025
SistersOREGON52025

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