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Species · Oregon · BBS 2025 Release · 1966–2024

Pelagic Cormorant Population Trend in Oregon

All statesWetland birds

Pelagic Cormorant in Oregon has surged: up 108% on the route-weighted index since 1976.

+108%Since 1976TrendPercent 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 StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
20YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Pelagic Cormorant Trends in OregonNotable 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 →

Pelagic Cormorant has surged in Oregon: up 108% on the route-weighted index since 1976.

Pelagic Cormorant Population Forecast in Oregon

If the recent trend holds, Pelagic Cormorant in Oregon is projected to stay roughly flat through 2029, near 0.11 (95% range 0.00–0.35). A 5-year backtest shows a typical error of ±120.4%, with 60% of held-out values landing inside the 95% band.

n/aChange 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 →
0.11Projected 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 →
0.00–0.3595% 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 →
±120.4%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, Pelagic Cormorant in Oregon is projected to stay roughly flat through 2029, near 0.11 (95% range 0.00–0.35). A 5-year backtest shows a typical error of ±120.4%, with 60% of held-out values landing inside the 95% band.19732029
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 →
20250.100.000.34
20260.100.000.34
20270.100.000.35
20280.110.000.35
20290.110.000.35

Pelagic Cormorant Survey Routes in Oregon

Routes recording Pelagic Cormorant in Oregon.
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 →
Wedderburn4020191973
Hauser119761976
Glasgow120242012
Hazel Camp120072007

Pelagic Cormorant Population Trend in Other States

alaskacaliforniawashington

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