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

Double-crested Cormorant Population Trend in Minnesota

All statesWetland birds

Double-crested Cormorant in Minnesota has surged: up 241% on the route-weighted index since 1975.

+241%Since 1975TrendPercent 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 →
54Routes 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 →
50YearsYears 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 MinnesotaNotable 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 Minnesota: up 241% on the route-weighted index since 1975.

Double-crested Cormorant Population Forecast in Minnesota

If the recent trend holds, Double-crested Cormorant in Minnesota is projected to rise about 15× by 2029 — from 0.11 in 2024 to a central estimate of 1.6 (95% range 0.00–3.5). A 5-year backtest shows a typical error of ±994.8%, with 40% of held-out values landing inside the 95% band.

15×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 →
1.6Projected 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 →
0.00–3.595% 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 →
±994.8%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 Minnesota is projected to rise about 15× by 2029 — from 0.11 in 2024 to a central estimate of 1.6 (95% range 0.00–3.5). A 5-year backtest shows a typical error of ±994.8%, with 40% 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 →
20251.60.003.5
20261.60.003.5
20271.60.003.5
20281.60.003.5
20291.60.003.5

Double-crested Cormorant Survey Routes in Minnesota

Routes recording Double-crested Cormorant in Minnesota.
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 →
Big Stone4120121995
Hart Lake3819971995
Worthington2820222004
Mcgregor2419931993
Pine River2219911990
Evergreen1320051985
Wylie1219981998
Le Center720231993
Princeton620132003
Glenwood620191993
Cromwell520012001
Millville419971997
Dawson420191982
Sherburne Nr320231990
Ash Creek320131990
Gluek320191973
Edwards320231984
Glyndon320231978
Tenney320161978
Nett Lake320162016
New London320121994
Chokio North320242005
Cass Lake319901990
Osseo220171981
Chokio220241978

Double-crested Cormorant Population Trend in Other States

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

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