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Species · Massachusetts · BBS 2025 Release · 1966–2024

Double-crested Cormorant Population Trend in Massachusetts

All statesWetland birds

Double-crested Cormorant in Massachusetts has surged: up 100% on the route-weighted index since 1971.

+100%Since 1971
23Routes In State
47Years

Notable Double-crested Cormorant Trends in Massachusetts

long arc increasecomputed index

Double-crested Cormorant has surged in Massachusetts: up 100% on the route-weighted index since 1971.

Double-crested Cormorant Population Forecast in Massachusetts

If the recent trend holds, Double-crested Cormorant in Massachusetts is projected to rise about 516% by 2029 — from 0.07 in 2024 to a central estimate of 0.41 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±180.5%, with 100% of held-out values landing inside the 95% band.

+516%Change by 2029
0.41Projected 2029 index
0.00–1.495% range
±180.5%Backtest error
19692029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20250.430.001.5
20260.420.001.5
20270.420.001.4
20280.420.001.4
20290.410.001.4

Double-crested Cormorant Survey Routes in Massachusetts

Routes recording Double-crested Cormorant in Massachusetts.
Chilmark2219831969
Hancock1220132013
Newburyport1120221980
Littleton920002000
Cape Cod Ns519961992
Brockton420181986
Chesterfield420132013
Wellfleet 2320192019
Marion220231970
Maynard220061998
E Pepperell219921990
Gay Head220211996
N. Andover220181995
E Dennis120191996
Wellfleet119981992
Prattville120061977
N Oxford120172017
Mansfield120211998
Belchertown120012001
Warren120082004
N Orange120242024
Holden120091988
Warren 2120212016

Double-crested Cormorant Population Trend in Other States

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

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