Species · Montana · BBS 2025 Release · 1966–2024
Common Tern Population Trend in Montana
Common Tern in Montana has collapsed: down 83% on the route-weighted index since 1976.
-83%Since 1976
10Routes In State
19Years
Notable Common Tern Trends in Montana
long arc declinecomputed index
Common Tern has collapsed in Montana: down 83% on the route-weighted index since 1976.
Common Tern Population Forecast in Montana
If the recent trend holds, Common Tern in Montana is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±231.2%, with 100% of held-out values landing inside the 95% band.
n/aChange by 2029
0.00Projected 2029 index
0.00–0.1295% range
±231.2%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.00 | 0.00 | 0.12 |
| 2026 | 0.00 | 0.00 | 0.12 |
| 2027 | 0.00 | 0.00 | 0.12 |
| 2028 | 0.00 | 0.00 | 0.12 |
| 2029 | 0.00 | 0.00 | 0.12 |
Common Tern Survey Routes in Montana
| St Mary | 4 | 1968 | 1968 |
| Ester Lake | 3 | 2016 | 2016 |
| Great Falls | 2 | 2003 | 1973 |
| Brusett | 2 | 1986 | 1983 |
| Jordan | 2 | 2000 | 1968 |
| Virgelle | 1 | 1990 | 1990 |
| Cleveland | 1 | 2013 | 2013 |
| Pablo Res. | 1 | 2024 | 2024 |
| Augusta | 1 | 2013 | 1976 |
| Chinook | 1 | 2018 | 2018 |
Common Tern Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.