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

Double-crested Cormorant In Sierra Madre Occidental

All regionsSierra Madre OccidentalWetland birds

Double-crested Cormorant in Sierra Madre Occidental has declined: down 43% on the route-weighted index since 1993.

-43%Since 1993TrendPercent 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 →
5Routes 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 →
28YearsYears 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 Double-crested Cormorant in Sierra Madre Occidental. See the full index history below.

Forecast

If the recent trend holds, Double-crested Cormorant in Sierra Madre Occidental is projected to rise about 737% by 2029 — from 0.06 in 2024 to a central estimate of 0.47 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±1669.5%, with 60% of held-out values landing inside the 95% band.

+737%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 →
0.47Projected 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 →
0.00–1.595% 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 →
±1669.5%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, Double-crested Cormorant in Sierra Madre Occidental is projected to rise about 737% by 2029 — from 0.06 in 2024 to a central estimate of 0.47 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±1669.5%, with 60% of held-out values landing inside the 95% band.19872029
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 →
20250.470.001.5
20260.470.001.5
20270.470.001.5
20280.470.001.5
20290.470.001.5

Routes In Sierra Madre Occidental

Routes recording Double-crested Cormorant 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 →
Peña BlancaARIZONA122001
PrescottARIZONA62017
WilliamsARIZONA12009
AlpineARIZONA12022
Carr MtnARIZONA12024

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