Species · Oregon · BBS 2025 Release · 1966–2024
Forster's Tern Population Trend in Oregon
Forster's Tern in Oregon has fallen sharply: down 67% on the route-weighted index since 1971.
-67%Since 1971
19Routes In State
54Years
Notable Forster's Tern Trends in Oregon
long arc declinecomputed index
Forster's Tern has fallen sharply in Oregon: down 67% on the route-weighted index since 1971.
Forster's Tern Population Forecast in Oregon
If the recent trend holds, Forster's Tern in Oregon is projected to fall about 100% by 2029 — from 0.16 in 2024 to a central estimate of 0.00 (95% range 0.00–0.59). A 5-year backtest shows a typical error of ±210.1%, with 100% of held-out values landing inside the 95% band.
-100%Change by 2029
0.00Projected 2029 index
0.00–0.5995% range
±210.1%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.00 | 0.00 | 0.59 |
| 2026 | 0.00 | 0.00 | 0.59 |
| 2027 | 0.00 | 0.00 | 0.59 |
| 2028 | 0.00 | 0.00 | 0.59 |
| 2029 | 0.00 | 0.00 | 0.59 |
Forster's Tern Survey Routes in Oregon
| Fish Lake | 14 | 2024 | 1980 |
| Princeton | 11 | 1985 | 1972 |
| Lapham Res. | 10 | 2022 | 2006 |
| Malheur Nwr | 10 | 1992 | 1987 |
| Blizzard Gap | 7 | 2023 | 1984 |
| Trout Creek | 7 | 2000 | 2000 |
| Merrill | 5 | 2013 | 1996 |
| Warner Vally | 4 | 2019 | 1994 |
| Modoc Point | 3 | 2018 | 1970 |
| Dell Spring | 2 | 1980 | 1969 |
| Joseph | 2 | 1997 | 1997 |
| Harney Lake | 2 | 2023 | 1993 |
| Ordnance | 1 | 1976 | 1975 |
| Bly | 1 | 1990 | 1990 |
| Crane | 1 | 2024 | 2024 |
| Catlow Rim | 1 | 2005 | 1996 |
| Umatilla | 1 | 2022 | 2022 |
| Sheaville | 1 | 2018 | 2013 |
| Chinchalo | 1 | 2015 | 1993 |
Forster's Tern Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.