Species · New Hampshire · BBS 2025 Release · 1966–2024
Double-crested Cormorant Population Trend in New Hampshire
Double-crested Cormorant in New Hampshire has held roughly steady: down 6% on the route-weighted index since 1982.
-6%Since 1982
12Routes In State
34Years
Notable Double-crested Cormorant Trends in New Hampshire
No notable trend signals for Double-crested Cormorant in New Hampshire. See the full index history below.
Double-crested Cormorant Population Forecast in New Hampshire
If the recent trend holds, Double-crested Cormorant in New Hampshire is projected to fall about 76% by 2028 — from 0.30 in 2023 to a central estimate of 0.07 (95% range 0.00–0.28). A 5-year backtest shows a typical error of ±41.4%, with 80% of held-out values landing inside the 95% band.
-76%Change by 2028
0.07Projected 2028 index
0.00–0.2895% range
±41.4%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2024 | 0.08 | 0.00 | 0.29 |
| 2025 | 0.08 | 0.00 | 0.29 |
| 2026 | 0.08 | 0.00 | 0.29 |
| 2027 | 0.07 | 0.00 | 0.28 |
| 2028 | 0.07 | 0.00 | 0.28 |
Double-crested Cormorant Survey Routes in New Hampshire
| Peterborough | 6 | 1975 | 1975 |
| Dover | 3 | 2018 | 1982 |
| Epsom | 3 | 2023 | 1989 |
| Milan | 3 | 2023 | 2002 |
| Marlow | 2 | 1992 | 1992 |
| Strafford | 1 | 2023 | 2011 |
| Mt Chocorua | 1 | 2021 | 2021 |
| Walpole | 1 | 2014 | 2014 |
| Lempster | 1 | 1999 | 1999 |
| Jefferson Hl | 1 | 2017 | 1987 |
| Dixvil Notch | 1 | 2016 | 2016 |
| Clarksville | 1 | 1974 | 1974 |
Double-crested Cormorant Population Trend in Other States
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Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.