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

Pied-billed Grebe In Sierra Madre Occidental

All regionsSierra Madre OccidentalWetland birds

Pied-billed Grebe in Sierra Madre Occidental has edged down: down 16% on the route-weighted index since 1992.

-16%Since 1992TrendPercent 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 →
4Routes 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 →
23YearsYears 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 →

No notable trend signals for Pied-billed Grebe in Sierra Madre Occidental. See the full index history below.

Pied-billed Grebe In Sierra Madre Occidental Population Forecast

If the recent trend holds, Pied-billed Grebe in Sierra Madre Occidental is projected to fall about 59% by 2030 — from 0.26 in 2025 to a central estimate of 0.11 (95% range 0.00–0.21). A 5-year backtest shows a typical error of ±128.3%, with 80% of held-out values landing inside the 95% band.

-59%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 →
0.11Projected 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 →
0.00–0.2195% 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 →
±128.3%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, Pied-billed Grebe in Sierra Madre Occidental is projected to fall about 59% by 2030 — from 0.26 in 2025 to a central estimate of 0.11 (95% range 0.00–0.21). A 5-year backtest shows a typical error of ±128.3%, with 80% of held-out values landing inside the 95% band.19852030
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 →
20260.110.000.21
20270.110.000.21
20280.110.000.21
20290.110.000.21
20300.110.000.21

Routes In Sierra Madre Occidental

Routes recording Pied-billed Grebe 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 →
AlpineARIZONA72025
PrescottARIZONA12019
RedingtonARIZONA11994
Carr MtnARIZONA12015

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