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Species · BCR 16 · BBS 2026 Release · 1966–2025

MacGillivray's Warbler In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauForest birds

MacGillivray's Warbler in Southern Rockies / Colorado Plateau has surged: up 107% on the route-weighted index since 1970.

+107%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 →
140Routes 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 →

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 →

MacGillivray's Warbler has surged in Southern Rockies / Colorado Plateau: up 107% on the route-weighted index since 1970.

MacGillivray's Warbler In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, MacGillivray's Warbler in Southern Rockies / Colorado Plateau is projected to stay roughly flat through 2030, near 2.1 (95% range 1.3–2.9). A 5-year backtest shows a typical error of ±36.2%, with 80% of held-out values landing inside the 95% band.

-1%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 →
2.1Projected 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 →
1.3–2.995% 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 →
±36.2%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 Southern Rockies / Colorado Plateau is projected to stay roughly flat through 2030, near 2.1 (95% range 1.3–2.9). A 5-year backtest shows a typical error of ±36.2%, with 80% 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 →
20262.01.22.8
20272.01.22.8
20282.01.22.8
20292.11.32.9
20302.11.32.9

Routes In Southern Rockies / Colorado Plateau

Routes recording MacGillivray's Warbler in Southern Rockies / Colorado Plateau.
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 →
Lost Cr. ResUTAH322018
Beck 2UTAH212025
YampaCOLORADO162023
AspenCOLORADO132025
UncompahgreCOLORADO122025
Dunckley PasCOLORADO122025
FlattopsCOLORADO122025
Heber Mtn.UTAH122025
Blackhead PkCOLORADO102025
ThomasvilleCOLORADO102025
Marshall PasCOLORADO102014
Uintah NfUTAH101994
Ryan ParkWYOMING102025
Dolores RivCOLORADO92025
Mcphee Res.COLORADO92025
Book RidgeUTAH92006
Douglas PassCOLORADO82024
HeeneyCOLORADO82019
BeckUTAH81987
Red CliffCOLORADO72025
Baxter PassCOLORADO72024
AngoraCOLORADO72025
NuclaCOLORADO72025
BeaverUTAH72025
GooseberryUTAH72025

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