Western Grebe
Western Grebe has fallen sharply: down 71% on the route-weighted index since 1988.
About the Western Grebe
The Western Grebe (Aechmophorus occidentalis) is a North American member of the Grebes (Podicipedidae). In this analysis it is grouped with the wetland birds.
- Size
- 9–21.5 in long (23–55 cm) — a diving water bird (typical for the family)
- Habitat
- Marshes, ponds, lakeshores and other freshwater wetlands.
- Diet
- Aquatic invertebrates, small fish, frogs and plant matter.
- Range
- Recorded on 221 Breeding Bird Survey routes across 16 states, most concentrated in the Great Basin.
- Family
- Podicipedidae · Wetland birds
Notable Western Grebe Trends
Western Grebe has fallen sharply in surveyed states: down 71% on the route-weighted index since 1988.
Western Grebe Population Forecast
If the recent trend holds, Western Grebe is projected to rise about 142% by 2029 — from 0.07 in 2024 to a central estimate of 0.17 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±156.1%, with 100% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.19 | 0.00 | 0.46 |
| 2026 | 0.18 | 0.00 | 0.46 |
| 2027 | 0.18 | 0.00 | 0.45 |
| 2028 | 0.18 | 0.00 | 0.45 |
| 2029 | 0.17 | 0.00 | 0.44 |
Where the Western Grebe Is Detected
BBS routes recording Western Grebe, sized by most recent count.
Western Grebe Population Trend by State
| Arizona | -11% | 1999 | 4 |
| California | -80% | 1988 | 38 |
| Colorado | +3% | 1992 | 21 |
| Idaho | -91% | 1988 | 15 |
| Kansas | insufficient data | n/a | 1 |
| Minnesota | insufficient data | n/a | 5 |
| Montana | +89% | 1991 | 11 |
| Nebraska | -17% | 1994 | 5 |
| Nevada | -93% | 1994 | 7 |
| New Mexico | -24% | 2000 | 4 |
| North Dakota | +149% | 1988 | 22 |
| Oregon | -94% | 1988 | 17 |
| South Dakota | -67% | 1988 | 14 |
| Utah | +230% | 1992 | 23 |
| Washington | -61% | 1990 | 7 |
| Wyoming | +43% | 1989 | 27 |
Western Grebe Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Northern Pacific Rainforest | -92% | 1989 | 7 |
| Great Basin | -92% | 1988 | 53 |
| Northern Rockies | -82% | 1988 | 39 |
| Prairie Potholes | -15% | 1988 | 31 |
| Sierra Nevada | +7% | 1988 | 4 |
| Southern Rockies / Colorado Plateau | +202% | 1990 | 29 |
| Badlands and Prairies | +55% | 1991 | 18 |
| Shortgrass Prairie | -37% | 1996 | 7 |
| Central Mixed Grass Prairie | +6% | 1994 | 6 |
| Coastal California | +67% | 1988 | 19 |
| Sonoran and Mojave Deserts | +99% | 1997 | 5 |
Western Grebe Conservation Status
Our route-weighted index shows it down about 71% since 1988.
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.