Species · BCR 15 · BBS 2025 Release · 1966–2024
Common Merganser In Sierra Nevada
Common Merganser in Sierra Nevada has surged: up 84% on the route-weighted index since 1972.
+84%Since 1972
17Routes In Region
43Years
Notable Signals
long arc increasecomputed index
Common Merganser has surged in Sierra Nevada: up 84% on the route-weighted index since 1972.
Forecast
If the recent trend holds, Common Merganser in Sierra Nevada is projected to fall about 72% by 2028 — from 0.82 in 2023 to a central estimate of 0.23 (95% range 0.00–0.53). A 5-year backtest shows a typical error of ±96.7%, with 40% of held-out values landing inside the 95% band.
-72%Change by 2028
0.23Projected 2028 index
0.00–0.5395% range
±96.7%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2024 | 0.22 | 0.00 | 0.53 |
| 2025 | 0.23 | 0.00 | 0.53 |
| 2026 | 0.23 | 0.00 | 0.53 |
| 2027 | 0.23 | 0.00 | 0.53 |
| 2028 | 0.23 | 0.00 | 0.53 |
Routes In Sierra Nevada
| Genesee | CALIFORNIA | 6 | 2023 |
| Riverton | CALIFORNIA | 4 | 2017 |
| Eagle Lake | CALIFORNIA | 3 | 2023 |
| Woodfords | CALIFORNIA | 3 | 2022 |
| Chilcoot | CALIFORNIA | 3 | 2023 |
| Meadow Valley | CALIFORNIA | 2 | 2023 |
| Little Truckee | CALIFORNIA | 2 | 2017 |
| Dardanelle | CALIFORNIA | 1 | 2014 |
| Bass Lake | CALIFORNIA | 1 | 1981 |
| Johnsville | CALIFORNIA | 1 | 2021 |
| Silver City | CALIFORNIA | 1 | 2013 |
| Tuolumne Grove | CALIFORNIA | 1 | 2016 |
| Sattley | CALIFORNIA | 1 | 2009 |
| Butte Meadow | CALIFORNIA | 1 | 2000 |
| Paxton | CALIFORNIA | 1 | 2022 |
| Strawberry | CALIFORNIA | 1 | 2015 |
| Last Chance | CALIFORNIA | 1 | 2009 |
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.