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Species · BCR 16 · BBS 2025 Release · 1966–2024

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 82% on the route-weighted index since 1970.

+82%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 →
138Routes 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 →

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 82% 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 rise about 32% by 2029 — from 1.6 in 2024 to a central estimate of 2.0 (95% range 1.2–2.9). A 5-year backtest shows a typical error of ±51.6%, with 60% of held-out values landing inside the 95% band.

+32%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 →
2.0Projected 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 →
1.2–2.995% 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 →
±51.6%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 rise about 32% by 2029 — from 1.6 in 2024 to a central estimate of 2.0 (95% range 1.2–2.9). A 5-year backtest shows a typical error of ±51.6%, 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 →
20252.01.22.8
20262.01.22.8
20272.01.22.8
20282.01.22.8
20292.01.22.9

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
YampaCOLORADO162023
Mcphee Res.COLORADO142024
AspenCOLORADO122024
Dunckley PasCOLORADO112024
Beck 2UTAH112018
Dolores RivCOLORADO102024
Marshall PasCOLORADO102014
Uintah NfUTAH101994
Heber Mtn.UTAH102024
Book RidgeUTAH92006
Douglas PassCOLORADO82024
Wilson CreekCOLORADO82024
Ragged Mtn.COLORADO82019
HeeneyCOLORADO82019
BeckUTAH81987
SoapstoneUTAH82024
Baxter PassCOLORADO72024
Ant Flat-Ogden CanUTAH72023
Lost LakeCOLORADO62024
CastletonCOLORADO62024
Comanche PkCOLORADO62024
Owl Creek PassCOLORADO62024
Willow PeakCOLORADO52021
Guanella PasCOLORADO52024

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