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Species · Pennsylvania · BBS 2025 Release · 1966–2024

Double-crested Cormorant Population Trend in Pennsylvania

All statesWetland birds

Double-crested Cormorant in Pennsylvania has held roughly steady: down 1% on the route-weighted index since 1991.

-1%Since 1991
31Routes In State
30Years

Notable Double-crested Cormorant Trends in Pennsylvania

No notable trend signals for Double-crested Cormorant in Pennsylvania. See the full index history below.

Double-crested Cormorant Population Forecast in Pennsylvania

If the recent trend holds, Double-crested Cormorant in Pennsylvania is projected to fall about 26% by 2029 — from 0.09 in 2024 to a central estimate of 0.07 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±469.2%, with 100% of held-out values landing inside the 95% band.

-26%Change by 2029
0.07Projected 2029 index
0.00–0.1595% range
±469.2%Backtest error
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 index95% low95% high
20250.060.000.15
20260.070.000.15
20270.070.000.15
20280.070.000.15
20290.070.000.15

Double-crested Cormorant Survey Routes in Pennsylvania

Routes recording Double-crested Cormorant in Pennsylvania.
Canadensis1320152015
Arnot1020122000
Rosecrans820031999
Brunnerville820091973
Rush720242001
Mount Joy320112011
Brick Tavern320122012
Middletown320141998
Greentown220141991
Brunnerville 2220172010
Espyville120232002
Whig Hill120152015
Berwick120012000
Teepleville119921992
N Washington120222022
Lovelton120182018
Pottersdale120142002
Leola120242024
Ramsey119941994
Mawr Glen120082008
Landisburg120182002
Beaver120182009
Parkwood120162016
Schaefferstown 2120142014
Kaylor120162016

Double-crested Cormorant Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonrhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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