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

Grace's Warbler In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauForest birds

Grace's Warbler in Southern Rockies / Colorado Plateau has surged: up 101% on the route-weighted index since 1970.

+101%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 →
50Routes 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 →
53YearsYears 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 →

Grace's Warbler has surged in Southern Rockies / Colorado Plateau: up 101% on the route-weighted index since 1970.

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

If the recent trend holds, Grace's Warbler in Southern Rockies / Colorado Plateau is projected to rise about 33% by 2029 — from 0.67 in 2024 to a central estimate of 0.89 (95% range 0.51–1.3). A 5-year backtest shows a typical error of ±16.7%, with 100% of held-out values landing inside the 95% band.

+33%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 →
0.89Projected 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 →
0.51–1.395% 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 →
±16.7%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, Grace's Warbler in Southern Rockies / Colorado Plateau is projected to rise about 33% by 2029 — from 0.67 in 2024 to a central estimate of 0.89 (95% range 0.51–1.3). A 5-year backtest shows a typical error of ±16.7%, 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 →
20250.840.461.2
20260.850.471.2
20270.860.491.2
20280.880.501.3
20290.890.511.3

Routes In Southern Rockies / Colorado Plateau

Routes recording Grace'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 →
SawmillARIZONA372014
Bluewater LakeNEW-MEXICO302021
TsaileARIZONA282023
Mcphee Res.COLORADO162024
Haycamp MesaCOLORADO162024
GallinasNEW-MEXICO122021
Mt. TaylorNEW-MEXICO102012
CebollaNEW-MEXICO92023
Dry ParkARIZONA72024
VallecitosNEW-MEXICO72024
Mt. Taylor 2NEW-MEXICO72024
NuclaCOLORADO62024
Angel Fire 2NEW-MEXICO62024
Pagosa SpgsCOLORADO51975
Bryce CanyonUTAH52024
Cortez 2COLORADO42015
Ojo SarcoNEW-MEXICO42024
ZeniffARIZONA31968
Navajo LakeUTAH32022
Dixie NfUTAH32024
DeltaCOLORADO22021
DoloresCOLORADO21969
CortezCOLORADO22006
Blackhead PkCOLORADO21998
CokedaleCOLORADO22024

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