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

Grasshopper Sparrow In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauGrassland birds

Grasshopper Sparrow in Southern Rockies / Colorado Plateau has collapsed: down 99% on the route-weighted index since 1973.

-99%Since 1973TrendPercent 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 →
25Routes 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 →
33YearsYears 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 declinecomputed 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 →

Grasshopper Sparrow has collapsed in Southern Rockies / Colorado Plateau: down 99% on the route-weighted index since 1973.

Grasshopper Sparrow In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, Grasshopper Sparrow in Southern Rockies / Colorado Plateau is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±2226.8%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00Projected 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 →
0.00–1.395% 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 →
±2226.8%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, Grasshopper Sparrow in Southern Rockies / Colorado Plateau is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±2226.8%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.000.001.3
20260.000.001.3
20270.000.001.3
20280.000.001.3
20290.000.001.3

Routes In Southern Rockies / Colorado Plateau

Routes recording Grasshopper Sparrow 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 →
AltonahUTAH521993
PasturaNEW-MEXICO62015
MoffatCOLORADO42016
GardnerCOLORADO42002
BufordCOLORADO32023
Steamboat L.COLORADO32013
CapulinNEW-MEXICO31994
BrookhurstWYOMING32022
Round RockARIZONA21971
GallinasNEW-MEXICO21993
KamasUTAH21998
VernalUTAH22018
YampaCOLORADO12015
DeltaCOLORADO11980
ParlinCOLORADO12010
Wilson CreekCOLORADO12014
UncompahgreCOLORADO12003
San LuisCOLORADO11993
JensenUTAH12022
Heber Mtn.UTAH12012
AltonUTAH11997
BufordWYOMING12009
WarbonnetWYOMING11990
Fletcher PkWYOMING12024
Sybille CynWYOMING12015

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