BirdAnalyst
Species · Nevada · BBS 2025 Release · 1966–2024

Double-crested Cormorant Population Trend in Nevada

All statesWetland birds

Double-crested Cormorant in Nevada has collapsed: down 80% on the route-weighted index since 1978.

-80%Since 1978TrendPercent 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 →
9Routes 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 →
29YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Double-crested Cormorant Trends in NevadaNotable 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 →

Double-crested Cormorant has collapsed in Nevada: down 80% on the route-weighted index since 1978.

Double-crested Cormorant Population Forecast in Nevada

If the recent trend holds, Double-crested Cormorant in Nevada is projected to fall about 49% by 2027 — from 0.07 in 2022 to a central estimate of 0.04 (95% range 0.00–0.40). A 5-year backtest shows a typical error of ±211.8%, with 100% of held-out values landing inside the 95% band.

-49%Change by 2027TrendPercent 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 →
0.04Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.4095% 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 →
±211.8%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 Nevada is projected to fall about 49% by 2027 — from 0.07 in 2022 to a central estimate of 0.04 (95% range 0.00–0.40). A 5-year backtest shows a typical error of ±211.8%, with 100% of held-out values landing inside the 95% band.19702027
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 →
20230.060.000.43
20240.060.000.42
20250.050.000.41
20260.040.000.41
20270.040.000.40

Double-crested Cormorant Survey Routes in Nevada

Routes recording Double-crested Cormorant in Nevada.
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 →
Ruby Valley720011997
Dobbin Creek319871970
Ash Meadows220152015
Bald Mtn.120091995
Virgin Creek120012001
Nixon120221975
Ruby Valley 2120162006
Fallon120131992
Gardnerville120001998

Double-crested Cormorant Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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