BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

MacGillivray's Warbler In Great Basin

All regionsGreat BasinForest birds

MacGillivray's Warbler in Great Basin has increased: up 33% on the route-weighted index since 1970.

+33%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 →
56YearsYears 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 2029, near 1.9 (95% range 1.2–2.7). A 5-year backtest shows a typical error of ±16.3%, with 100% of held-out values landing inside the 95% band.

-5%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 →
1.9Projected 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 →
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 →
±16.3%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, MacGillivray's Warbler in Great Basin is projected to stay roughly flat through 2029, near 1.9 (95% range 1.2–2.7). A 5-year backtest shows a typical error of ±16.3%, with 100% 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 →
20251.91.12.6
20261.91.22.6
20271.91.22.6
20281.91.22.6
20291.91.22.7

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
SnowdenWASHINGTON282024
E. Mt. AdamsWASHINGTON282024
NewhalemWASHINGTON262024
Blewett PassWASHINGTON252024
Magic MtnIDAHO182024
GlacierWASHINGTON182024
Picture FlatOREGON172024
LeavenworthWASHINGTON152024
Lake ChelanWASHINGTON142024
Mt HoodOREGON132024
RimrockWASHINGTON122024
KendallWASHINGTON122024
L. WenatcheeWASHINGTON102024
Ruby ValleyNEVADA92001
Cascade RivWASHINGTON92006
RonaldWASHINGTON82024
MazamaWASHINGTON82022
ConcreteWASHINGTON82024
HawthorneNEVADA72001
White ChuckWASHINGTON72024
AlmoIDAHO62022
JarbidgeNEVADA62015
Comins LakeNEVADA62016
LakeviewOREGON62024

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