California Gull
California Gull has surged: up 360% on the route-weighted index since 1970.
About the California Gull
The California Gull (Larus californicus) is a North American member of the Gulls, Terns & Skimmers (Laridae). In this analysis it is grouped with the wetland birds.
- Size
- 8.5–31.5 in long (22–80 cm) — a long-winged waterbird (typical for the family)
- Habitat
- Marshes, ponds, lakeshores and other freshwater wetlands.
- Diet
- Aquatic invertebrates, small fish, frogs and plant matter.
- Range
- Recorded on 325 Breeding Bird Survey routes across 14 states, most concentrated in the Great Basin.
- Family
- Laridae · Wetland birds
Notable California Gull Trends
California Gull has surged in surveyed states: up 360% on the route-weighted index since 1970.
California Gull Population Forecast
If the recent trend holds, California Gull is projected to rise about 18% by 2029 — from 1.4 in 2024 to a central estimate of 1.6 (95% range 0.89–2.4). A 5-year backtest shows a typical error of ±44.7%, with 80% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 1.6 | 0.82 | 2.3 |
| 2026 | 1.6 | 0.84 | 2.4 |
| 2027 | 1.6 | 0.85 | 2.4 |
| 2028 | 1.6 | 0.87 | 2.4 |
| 2029 | 1.6 | 0.89 | 2.4 |
Where the California Gull Is Detected
BBS routes recording California Gull, sized by most recent count.
California Gull Population Trend by State
| Alaska | insufficient data | n/a | 3 |
| California | +26% | 1973 | 58 |
| Colorado | 148× | 1986 | 15 |
| Idaho | -94% | 1971 | 26 |
| Minnesota | insufficient data | n/a | 1 |
| Montana | -51% | 1970 | 43 |
| Nevada | +8% | 1973 | 12 |
| New Mexico | insufficient data | n/a | 1 |
| North Dakota | +59% | 1976 | 21 |
| Oregon | +201% | 1971 | 27 |
| South Dakota | -34% | 2004 | 3 |
| Utah | +299% | 1970 | 34 |
| Washington | +61% | 1980 | 35 |
| Wyoming | -11% | 1970 | 46 |
California Gull Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Northern Pacific Rainforest | +66% | 1972 | 25 |
| Great Basin | +7% | 1970 | 109 |
| Northern Rockies | +71% | 1970 | 62 |
| Prairie Potholes | +312% | 1971 | 39 |
| Sierra Nevada | -98% | 1974 | 10 |
| Southern Rockies / Colorado Plateau | 15× | 1974 | 26 |
| Badlands and Prairies | -49% | 1971 | 24 |
| Shortgrass Prairie | 13× | 1986 | 6 |
| Coastal California | 74× | 1973 | 21 |
| Sonoran and Mojave Deserts | -96% | 1993 | 3 |
California Gull Conservation Status
Our route-weighted index shows it up about 360% since 1970.
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.