Species · BCR 10 · BBS 2025 Release · 1966–2024
Common Merganser In Northern Rockies
Common Merganser in Northern Rockies has surged: up 99% on the route-weighted index since 1970.
+99%Since 1970
120Routes In Region
53Years
Notable Signals
long arc increasecomputed index
Common Merganser has surged in Northern Rockies: up 99% on the route-weighted index since 1970.
Forecast
If the recent trend holds, Common Merganser in Northern Rockies is projected to rise about 121% by 2029 — from 0.23 in 2024 to a central estimate of 0.52 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±56.1%, with 100% of held-out values landing inside the 95% band.
+121%Change by 2029
0.52Projected 2029 index
0.00–1.595% range
±56.1%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.53 | 0.00 | 1.5 |
| 2026 | 0.52 | 0.00 | 1.5 |
| 2027 | 0.52 | 0.00 | 1.5 |
| 2028 | 0.52 | 0.00 | 1.5 |
| 2029 | 0.52 | 0.00 | 1.5 |
Routes In Northern Rockies
| Cascade | IDAHO | 105 | 1984 |
| Hayden Val | WYOMING | 30 | 1986 |
| Harmony | WYOMING | 21 | 2022 |
| Yellowstone | WYOMING | 20 | 2022 |
| Colter Bay 2 | WYOMING | 16 | 2023 |
| Ninemile | MONTANA | 11 | 2024 |
| Ne Entrance | WYOMING | 9 | 2021 |
| Moran | WYOMING | 9 | 2016 |
| Beaverhead | MONTANA | 8 | 1997 |
| Mammoth | WYOMING | 7 | 2018 |
| Green River | WYOMING | 7 | 1984 |
| Kalispell | MONTANA | 6 | 2007 |
| Fish Creek | MONTANA | 6 | 2019 |
| Nowood | WYOMING | 6 | 2024 |
| N Fork Cda R | IDAHO | 5 | 2019 |
| Libby Dam | MONTANA | 5 | 2024 |
| Sullivan Lk | WASHINGTON | 5 | 1999 |
| Cape Horn | IDAHO | 4 | 2018 |
| Rochat Divde | IDAHO | 4 | 2023 |
| Red Rock | MONTANA | 4 | 1989 |
| Seedskadee | WYOMING | 4 | 2016 |
| Golden | IDAHO | 3 | 2008 |
| Centerville | IDAHO | 3 | 2019 |
| Augusta | MONTANA | 3 | 1997 |
| Swan Lake | MONTANA | 3 | 2023 |
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.