BirdAnalyst
Species · BCR 34 · BBS 2026 Release · 1966–2025

Great-tailed Grackle In Sierra Madre Occidental

All regionsSierra Madre OccidentalWetland birds

Great-tailed Grackle in Sierra Madre Occidental has collapsed: down 84% on the route-weighted index since 1973.

-84%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 →
18Routes 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 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 collapsed in Sierra Madre Occidental: down 84% on the route-weighted index since 1973.

Great-tailed Grackle In Sierra Madre Occidental Population Forecast

If the recent trend holds, Great-tailed Grackle in Sierra Madre Occidental is projected to fall about 52% by 2030 — from 1.2 in 2025 to a central estimate of 0.58 (95% range 0.00–3.9). A 5-year backtest shows a typical error of ±49.9%, with 100% of held-out values landing inside the 95% band.

-52%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 →
0.58Projected 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 →
0.00–3.995% 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 →
±49.9%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 Sierra Madre Occidental is projected to fall about 52% by 2030 — from 1.2 in 2025 to a central estimate of 0.58 (95% range 0.00–3.9). A 5-year backtest shows a typical error of ±49.9%, with 100% of held-out values landing inside the 95% band.19702030
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 →
20260.690.004.0
20270.670.003.9
20280.640.003.9
20290.610.003.9
20300.580.003.9

Routes In Sierra Madre Occidental

Routes recording Great-tailed Grackle in Sierra Madre Occidental.
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 →
Bartlett ResARIZONA142025
PomereneARIZONA52025
McnealARIZONA52025
PatagoniaARIZONA42025
PinetopARIZONA42003
Carr MtnARIZONA42021
Skull ValleyARIZONA32024
CutterARIZONA32014
AmadoARIZONA32025
PrescottARIZONA22021
Peña BlancaARIZONA21992
RedingtonARIZONA22010
Skull Valley 2ARIZONA22025
San SimonARIZONA11983
SunizonaARIZONA11996
WilliamsARIZONA12006
SahuaritaARIZONA12018
Sunizona 2ARIZONA12014

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