Species · New Hampshire · BBS 2025 Release · 1966–2024
Great Black-backed Gull Population Trend in New Hampshire
Great Black-backed Gull in New Hampshire has collapsed: down 81% on the route-weighted index since 1969.
-81%Since 1969
5Routes In State
23Years
Notable Great Black-backed Gull Trends in New Hampshire
long arc declinecomputed index
Great Black-backed Gull has collapsed in New Hampshire: down 81% on the route-weighted index since 1969.
Great Black-backed Gull Population Forecast in New Hampshire
If the recent trend holds, Great Black-backed Gull in New Hampshire is projected to stay roughly flat through 2010, near 0.00 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±55.1%, with 100% of held-out values landing inside the 95% band.
n/aChange by 2010
0.00Projected 2010 index
0.00–0.4495% range
±55.1%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2006 | 0.00 | 0.00 | 0.44 |
| 2007 | 0.00 | 0.00 | 0.44 |
| 2008 | 0.00 | 0.00 | 0.44 |
| 2009 | 0.00 | 0.00 | 0.44 |
| 2010 | 0.00 | 0.00 | 0.44 |
Great Black-backed Gull Survey Routes in New Hampshire
| Brentwood | 3 | 1983 | 1968 |
| Epsom | 3 | 1989 | 1985 |
| Dover | 1 | 1998 | 1967 |
| Strafford | 1 | 2005 | 1969 |
| Jefferson Hl | 1 | 1993 | 1993 |
Great Black-backed Gull Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.