Species · Massachusetts · BBS 2025 Release · 1966–2024
Great Black-backed Gull Population Trend in Massachusetts
Great Black-backed Gull in Massachusetts has fallen sharply: down 62% on the route-weighted index since 1970.
-62%Since 1970
12Routes In State
53Years
Notable Great Black-backed Gull Trends in Massachusetts
long arc declinecomputed index
Great Black-backed Gull has fallen sharply in Massachusetts: down 62% on the route-weighted index since 1970.
Great Black-backed Gull Population Forecast in Massachusetts
If the recent trend holds, Great Black-backed Gull in Massachusetts is projected to fall about 100% by 2028 — from 0.31 in 2023 to a central estimate of 0.00 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±85%, with 100% of held-out values landing inside the 95% band.
-100%Change by 2028
0.00Projected 2028 index
0.00–1.395% range
±85%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2024 | 0.04 | 0.00 | 1.3 |
| 2025 | 0.02 | 0.00 | 1.3 |
| 2026 | 0.01 | 0.00 | 1.3 |
| 2027 | 0.00 | 0.00 | 1.3 |
| 2028 | 0.00 | 0.00 | 1.3 |
Great Black-backed Gull Survey Routes in Massachusetts
| Chilmark | 22 | 1983 | 1969 |
| Gay Head | 4 | 2023 | 1996 |
| E Pepperell | 3 | 1989 | 1989 |
| Marion | 2 | 2011 | 1972 |
| Newburyport | 2 | 2022 | 1969 |
| Cape Cod Ns | 2 | 2007 | 1989 |
| E Dennis | 1 | 2013 | 1968 |
| Wellfleet | 1 | 2007 | 1970 |
| Prattville | 1 | 1997 | 1997 |
| Brockton | 1 | 2019 | 2019 |
| Wellfleet 2 | 1 | 2021 | 2019 |
| N. Andover | 1 | 1995 | 1995 |
Great Black-backed Gull Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.