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

Double-crested Cormorant Population Trend in Kansas

All statesWetland birds

Double-crested Cormorant in Kansas has surged: up 834% on the route-weighted index since 1977.

+834%Since 1977TrendPercent 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 →
17Routes 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 KansasNotable 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 Kansas: up 834% on the route-weighted index since 1977.

Double-crested Cormorant Population Forecast in Kansas

If the recent trend holds, Double-crested Cormorant in Kansas is projected to fall about 70% by 2028 — from 0.85 in 2023 to a central estimate of 0.26 (95% range 0.00–0.67). A 5-year backtest shows a typical error of ±93.3%, with 60% of held-out values landing inside the 95% band.

-70%Change by 2028TrendPercent 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 →
0.26Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.6795% 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 →
±93.3%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 Kansas is projected to fall about 70% by 2028 — from 0.85 in 2023 to a central estimate of 0.26 (95% range 0.00–0.67). A 5-year backtest shows a typical error of ±93.3%, with 60% of held-out values landing inside the 95% band.19692028
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 →
20240.250.000.66
20250.250.000.66
20260.250.000.66
20270.250.000.66
20280.260.000.67

Double-crested Cormorant Survey Routes in Kansas

Routes recording Double-crested Cormorant in Kansas.
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 →
Albert2220231969
Chapman1719811981
Barclay619981998
Trading Post420162008
Phillipsburg320172001
Coats220022002
Grantville220222022
Rock Creek220182018
Jewell119861986
Galesburg120232014
Logan120121977
Dalton119951995
Lakin119931993
Pittsburg120132006
Solomon120152015
Hays120082008
Severance120162001

Double-crested Cormorant Population Trend in Other States

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

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