BirdAnalyst
Species · BCR 10 · BBS 2026 Release · 1966–2025

Common Grackle In Northern Rockies

All regionsNorthern RockiesGeneralists

Common Grackle in Northern Rockies has fallen sharply: down 66% on the route-weighted index since 1970.

-66%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 →
74Routes 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 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 →

Common Grackle has fallen sharply in Northern Rockies: down 66% on the route-weighted index since 1970.

Common Grackle In Northern Rockies Population Forecast

If the recent trend holds, Common Grackle in Northern Rockies is projected to fall about 42% by 2030 — from 1.2 in 2025 to a central estimate of 0.72 (95% range 0.00–2.7). A 5-year backtest shows a typical error of ±32.2%, with 100% of held-out values landing inside the 95% band.

-42%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 →
0.72Projected 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 →
0.00–2.795% 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 →
±32.2%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, Common Grackle in Northern Rockies is projected to fall about 42% by 2030 — from 1.2 in 2025 to a central estimate of 0.72 (95% range 0.00–2.7). A 5-year backtest shows a typical error of ±32.2%, with 100% 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 →
20260.800.002.8
20270.780.002.8
20280.760.002.7
20290.740.002.7
20300.720.002.7

Routes In Northern Rockies

Routes recording Common Grackle 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 →
EtheteWYOMING362025
Church HillMONTANA252025
MidvaleWYOMING252025
BasinWYOMING212025
Clyde ParkMONTANA152025
OttoWYOMING122025
ErvayWYOMING112009
St MaryMONTANA91971
PathfinderWYOMING92022
NowoodWYOMING81995
Rawlins 2WYOMING82016
Patrick DrawWYOMING71974
TensleepWYOMING72025
Sand DrawWYOMING72025
BoulderMONTANA62024
Willow Creek 2MONTANA62025
Fort LoganMONTANA62022
CodyWYOMING62025
ClarkWYOMING62011
WalcottWYOMING62021
RaynesfordMONTANA52025
FontenelleWYOMING51992
Elk HornWYOMING52018
LysiteWYOMING52024
WorlandWYOMING52025

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