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

Great-tailed Grackle In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauGeneralists

Great-tailed Grackle in Southern Rockies / Colorado Plateau has fallen sharply: down 67% on the route-weighted index since 1973.

-67%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 →
32Routes 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 →
48YearsYears 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 →

Great-tailed Grackle has fallen sharply in Southern Rockies / Colorado Plateau: down 67% on the route-weighted index since 1973.

Great-tailed Grackle In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, Great-tailed Grackle in Southern Rockies / Colorado Plateau is projected to fall about 64% by 2029 — from 0.13 in 2024 to a central estimate of 0.05 (95% range 0.00–0.33). A 5-year backtest shows a typical error of ±111.5%, with 100% of held-out values landing inside the 95% band.

-64%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 →
0.05Projected 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 →
0.00–0.3395% 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 →
±111.5%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, Great-tailed Grackle in Southern Rockies / Colorado Plateau is projected to fall about 64% by 2029 — from 0.13 in 2024 to a central estimate of 0.05 (95% range 0.00–0.33). A 5-year backtest shows a typical error of ±111.5%, with 100% of held-out values landing inside the 95% band.19712029
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 →
20250.070.000.35
20260.060.000.35
20270.060.000.34
20280.050.000.34
20290.050.000.33

Routes In Southern Rockies / Colorado Plateau

Routes recording Great-tailed Grackle 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 →
ValenciaNEW-MEXICO251997
SeligmanARIZONA112024
DoloresCOLORADO41987
AlamosaCOLORADO42024
Ojo SarcoNEW-MEXICO32017
HatchUTAH32008
San LuisCOLORADO22023
Cortez 2COLORADO22014
CebollaNEW-MEXICO22022
ShiprockNEW-MEXICO22000
Stinking Lk.NEW-MEXICO21995
AztecNEW-MEXICO21989
Angel Fire 2NEW-MEXICO22018
Willow CreekUTAH21997
MoabUTAH22001
HannaUTAH22024
Wellington 3UTAH22013
HuntARIZONA12000
Castle ButteARIZONA11995
Peach SpringARIZONA12023
MoffatCOLORADO12010
FalfaCOLORADO12011
Pagosa SpgsCOLORADO11982
FruitaCOLORADO12007
CortezCOLORADO12008

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