BirdAnalyst
Species · BCR 34 · BBS 2025 Release · 1966–2024

Great-tailed Grackle In Sierra Madre Occidental

All regionsSierra Madre OccidentalGeneralists

Great-tailed Grackle in Sierra Madre Occidental has collapsed: down 89% on the route-weighted index since 1973.

-89%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 →
17Routes 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 →
53YearsYears 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 89% 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 32% by 2029 — from 0.83 in 2024 to a central estimate of 0.56 (95% range 0.00–3.9). A 5-year backtest shows a typical error of ±44%, with 100% of held-out values landing inside the 95% band.

-32%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 →
0.56Projected 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 →
0.00–3.995% 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 →
±44%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 32% by 2029 — from 0.83 in 2024 to a central estimate of 0.56 (95% range 0.00–3.9). A 5-year backtest shows a typical error of ±44%, with 100% of held-out values landing inside the 95% band.19702029
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 →
20250.680.004.0
20260.650.004.0
20270.620.003.9
20280.590.003.9
20290.560.003.9

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 →
PomereneARIZONA102024
PinetopARIZONA42003
AmadoARIZONA42023
Carr MtnARIZONA42021
Skull ValleyARIZONA32024
CutterARIZONA32014
PrescottARIZONA22021
Peña BlancaARIZONA21992
RedingtonARIZONA22010
San SimonARIZONA11983
PatagoniaARIZONA12024
SunizonaARIZONA11996
WilliamsARIZONA12006
Bartlett ResARIZONA12023
SahuaritaARIZONA12018
McnealARIZONA12024
Sunizona 2ARIZONA12014

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