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Species · Arizona · BBS 2026 Release · 1966–2025

Double-crested Cormorant Population Trend in Arizona

All statesWetland birds

Double-crested Cormorant in Arizona has surged: up 113% on the route-weighted index since 1991.

+113%Since 1991TrendPercent 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 →
35YearsYears 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 ArizonaNotable 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 →

Double-crested Cormorant has surged in Arizona: up 113% on the route-weighted index since 1991.

Double-crested Cormorant Population Forecast in Arizona

If the recent trend holds, Double-crested Cormorant in Arizona is projected to rise about 207% by 2030 — from 0.24 in 2025 to a central estimate of 0.75 (95% range 0.00–1.9). A 5-year backtest shows a typical error of ±2282.4%, with 80% of held-out values landing inside the 95% band.

+207%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 →
0.75Projected 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 →
0.00–1.995% 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 →
±2282.4%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 Arizona is projected to rise about 207% by 2030 — from 0.24 in 2025 to a central estimate of 0.75 (95% range 0.00–1.9). A 5-year backtest shows a typical error of ±2282.4%, with 80% of held-out values landing inside the 95% band.19772030
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 →
20260.690.001.8
20270.700.001.8
20280.720.001.8
20290.730.001.8
20300.750.001.9

Double-crested Cormorant Survey Routes in Arizona

Routes recording Double-crested Cormorant in Arizona.
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 →
Cutter 215520182015
Alamo Res.1620162014
Peña Blanca1220011997
Palo Verde920122012
Alpine920252019
Willow Beach 2720172016
Prescott620171987
Red Rock520012001
New River420051999
Araby220112011
Carr Mtn120241994
Palo Verde 2120242017
Laguna120181977
Casa Grande119951995
Williams120252009

Double-crested Cormorant Population Trend in Other States

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

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