BirdAnalyst
Species · BCR 10 · BBS 2025 Release · 1966–2024

Grasshopper Sparrow In Northern Rockies

All regionsNorthern RockiesGrassland birds

Grasshopper Sparrow in Northern Rockies has surged: up 142% on the route-weighted index since 1972.

+142%Since 1972TrendPercent 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 →
71Routes 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 →
54YearsYears 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 →

Grasshopper Sparrow has surged in Northern Rockies: up 142% on the route-weighted index since 1972.

Forecast

If the recent trend holds, Grasshopper Sparrow in Northern Rockies is projected to rise about 87% by 2029 — from 0.21 in 2024 to a central estimate of 0.40 (95% range 0.07–0.73). A 5-year backtest shows a typical error of ±91.3%, with 80% of held-out values landing inside the 95% band.

+87%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 →
0.40Projected 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 →
0.07–0.7395% 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 →
±91.3%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, Grasshopper Sparrow in Northern Rockies is projected to rise about 87% by 2029 — from 0.21 in 2024 to a central estimate of 0.40 (95% range 0.07–0.73). A 5-year backtest shows a typical error of ±91.3%, with 80% 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 →
20250.390.050.72
20260.390.060.72
20270.390.060.73
20280.400.060.73
20290.400.070.73

Routes In Northern Rockies

Routes recording Grasshopper Sparrow in Northern Rockies.
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 →
Red RockMONTANA152003
LaurelMONTANA112022
Muddy CreekMONTANA112015
Crane CreekIDAHO92019
WorlandWYOMING92024
NowoodWYOMING81990
PolsonMONTANA72024
Elk HornWYOMING72018
CentervilleIDAHO51972
CodyWYOMING52018
Crazy WomanWYOMING52024
EtheteWYOMING52002
Gas HillsWYOMING52012
Wolf CreekMONTANA42022
UnityOREGON41994
LaurierWASHINGTON42022
OttoWYOMING42014
FontenelleWYOMING41987
GeboWYOMING41988
ArmintoWYOMING42024
Pablo Res.MONTANA32023
Deer ParkWASHINGTON32015
Mtn ViewWYOMING31987
MaybellCOLORADO22008
GlenMONTANA22023

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