Species · Delaware · BBS 2025 Release · 1966–2024
Herring Gull Population Trend in Delaware
Herring Gull in Delaware has collapsed: down 77% on the route-weighted index since 1968.
-77%Since 1968
12Routes In State
48Years
Notable Herring Gull Trends in Delaware
long arc declinecomputed index
Herring Gull has collapsed in Delaware: down 77% on the route-weighted index since 1968.
Herring Gull Population Forecast in Delaware
If the recent trend holds, Herring Gull in Delaware is projected to fall about 100% by 2029 — from 0.40 in 2024 to a central estimate of 0.00 (95% range 0.00–10). A 5-year backtest shows a typical error of ±69.2%, with 100% of held-out values landing inside the 95% band.
-100%Change by 2029
0.00Projected 2029 index
0.00–1095% range
±69.2%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.00 | 0.00 | 10 |
| 2026 | 0.00 | 0.00 | 10 |
| 2027 | 0.00 | 0.00 | 10 |
| 2028 | 0.00 | 0.00 | 10 |
| 2029 | 0.00 | 0.00 | 10 |
Herring Gull Survey Routes in Delaware
| Mt Pleasant | 22 | 1990 | 1988 |
| Bethany Bch | 12 | 1990 | 1966 |
| Blackbird | 9 | 2009 | 1994 |
| Milton | 5 | 1977 | 1971 |
| Pepperbox | 3 | 2016 | 1999 |
| Harrington | 2 | 2018 | 1966 |
| Dover | 2 | 1979 | 1966 |
| Holleyville | 2 | 1995 | 1981 |
| Pepperbox 2 | 2 | 2024 | 2017 |
| Wilmington | 1 | 1967 | 1967 |
| Lowes Xrds | 1 | 1991 | 1966 |
| Georgetown | 1 | 2005 | 1997 |
Herring Gull Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.