Species · BCR 9 · BBS 2025 Release · 1966–2024
Caspian Tern In Great Basin
Caspian Tern in Great Basin has fallen sharply: down 67% on the route-weighted index since 1974.
-67%Since 1974
63Routes In Region
52Years
Notable Signals
long arc declinecomputed index
Caspian Tern has fallen sharply in Great Basin: down 67% on the route-weighted index since 1974.
Forecast
If the recent trend holds, Caspian Tern in Great Basin is projected to stay roughly flat through 2029, near 0.45 (95% range 0.00–0.97). A 5-year backtest shows a typical error of ±873.3%, with 40% of held-out values landing inside the 95% band.
n/aChange by 2029
0.45Projected 2029 index
0.00–0.9795% range
±873.3%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.45 | 0.00 | 0.96 |
| 2026 | 0.45 | 0.00 | 0.97 |
| 2027 | 0.45 | 0.00 | 0.97 |
| 2028 | 0.45 | 0.00 | 0.97 |
| 2029 | 0.45 | 0.00 | 0.97 |
Routes In Great Basin
| Iron Gate | CALIFORNIA | 79 | 2019 |
| Dorris | CALIFORNIA | 11 | 2019 |
| Tonasket | WASHINGTON | 9 | 1993 |
| Ruby Valley | NEVADA | 8 | 1999 |
| Harney Lake | OREGON | 6 | 2001 |
| Ingalls | CALIFORNIA | 5 | 1999 |
| Callao | UTAH | 4 | 2023 |
| Moses Lake | WASHINGTON | 4 | 2011 |
| L. Wenatchee | WASHINGTON | 4 | 2003 |
| Cedarville | CALIFORNIA | 3 | 1998 |
| Kyle Canyon | IDAHO | 3 | 1986 |
| Nixon | NEVADA | 3 | 2022 |
| Bald Mtn. | NEVADA | 3 | 2010 |
| Othello | WASHINGTON | 3 | 1991 |
| Honey Lake | CALIFORNIA | 2 | 1976 |
| Clear Lk Res | CALIFORNIA | 2 | 2018 |
| Acequia | IDAHO | 2 | 2002 |
| Umatilla | OREGON | 2 | 2022 |
| Malheur Nwr | OREGON | 2 | 1997 |
| Leamington | UTAH | 2 | 2016 |
| Quincy | WASHINGTON | 2 | 2012 |
| Ewan | WASHINGTON | 2 | 2019 |
| Ellensburg | WASHINGTON | 2 | 2009 |
| Odessa | WASHINGTON | 2 | 2007 |
| Lake Chelan | WASHINGTON | 2 | 1996 |
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.