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

Crissal Thrasher In Sierra Madre Occidental

All regionsSierra Madre OccidentalGeneralists

Crissal Thrasher in Sierra Madre Occidental has risen sharply: up 61% on the route-weighted index since 1974.

+61%Since 1974TrendPercent 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 →
21Routes 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 →
52YearsYears 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 →

Crissal Thrasher has risen sharply in Sierra Madre Occidental: up 61% on the route-weighted index since 1974.

Forecast

If the recent trend holds, Crissal Thrasher in Sierra Madre Occidental is projected to fall about 28% by 2029 — from 0.67 in 2024 to a central estimate of 0.48 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±48.1%, with 100% of held-out values landing inside the 95% band.

-28%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 →
0.48Projected 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 →
0.00–1.495% 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 →
±48.1%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, Crissal Thrasher in Sierra Madre Occidental is projected to fall about 28% by 2029 — from 0.67 in 2024 to a central estimate of 0.48 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±48.1%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.500.001.4
20260.490.001.4
20270.490.001.4
20280.480.001.4
20290.480.001.4

Routes In Sierra Madre Occidental

Routes recording Crissal Thrasher 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 →
PomereneARIZONA42024
San SimonARIZONA42024
Carr MtnARIZONA42023
McnealARIZONA32023
DragoonARIZONA31997
PrescottARIZONA22022
SunizonaARIZONA21978
Forest LakesARIZONA22019
AmadoARIZONA22013
PortalARIZONA22016
RuckerARIZONA21996
Vicks PeakNEW-MEXICO22023
Aztec PeakARIZONA11978
Peña BlancaARIZONA12001
PatagoniaARIZONA12024
Skull ValleyARIZONA12024
Bartlett ResARIZONA12024
CutterARIZONA12014
RedingtonARIZONA12019
Sunizona 2ARIZONA12024
MagdalenaNEW-MEXICO12000

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