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

Double-crested Cormorant Population Trend in Utah

All statesWetland birds

Double-crested Cormorant in Utah has collapsed: down 81% on the route-weighted index since 1985.

-81%Since 1985TrendPercent 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 →
15Routes 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 →
36YearsYears 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 UtahNotable 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 Utah: down 81% on the route-weighted index since 1985.

Double-crested Cormorant Population Forecast in Utah

If the recent trend holds, Double-crested Cormorant in Utah is projected to fall about 52% by 2029 — from 0.71 in 2024 to a central estimate of 0.34 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±72.4%, with 100% of held-out values landing inside the 95% band.

-52%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 →
0.34Projected 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 →
0.00–1.895% 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 →
±72.4%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, Double-crested Cormorant in Utah is projected to fall about 52% by 2029 — from 0.71 in 2024 to a central estimate of 0.34 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±72.4%, with 100% of held-out values landing inside the 95% band.19762029
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 →
20250.370.001.8
20260.360.001.8
20270.350.001.8
20280.350.001.8
20290.340.001.8

Double-crested Cormorant Survey Routes in Utah

Routes recording Double-crested Cormorant in Utah.
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 →
Neponset Res5520181995
Goshen4020241976
Callao1920161992
Saleratus Cr1120181995
Aneth1020082008
Bear River920231992
Oak City219991981
Woodruff220222005
Promontory120242011
Jensen120112002
Dixie Nf120082008
Grantsville120232006
Kamas120222013
Randolph120241992
Moab120172017

Double-crested Cormorant Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawashingtonwest-virginiawisconsinwyoming

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