Cassin's Sparrow
Cassin's Sparrow has risen sharply: up 61% on the route-weighted index since 1969.
About the Cassin's Sparrow
The Cassin's Sparrow (Peucaea cassinii) is a North American member of the New World Sparrows (Passerellidae). In this analysis it is grouped with the grassland birds.
- Size
- 4.5–7.5 in long (12–19 cm) — a small songbird (typical for the family)
- Habitat
- Open grasslands, prairie, pasture and hayfields.
- Diet
- Seeds and insects gathered from grasses and the ground.
- Range
- Recorded on 393 Breeding Bird Survey routes across 10 states, most concentrated in the Shortgrass Prairie.
- Family
- Passerellidae · Grassland birds
Notable Cassin's Sparrow Trends
Cassin's Sparrow has risen sharply in surveyed states: up 61% on the route-weighted index since 1969.
Cassin's Sparrow Population Forecast
If the recent trend holds, Cassin's Sparrow is projected to stay roughly flat through 2029, near 1.6 (95% range 0.78–2.5). A 5-year backtest shows a typical error of ±26.8%, with 100% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 1.6 | 0.76 | 2.5 |
| 2026 | 1.6 | 0.76 | 2.5 |
| 2027 | 1.6 | 0.77 | 2.5 |
| 2028 | 1.6 | 0.77 | 2.5 |
| 2029 | 1.6 | 0.78 | 2.5 |
Where the Cassin's Sparrow Is Detected
BBS routes recording Cassin's Sparrow, sized by most recent count.
Cassin's Sparrow Population Trend by State
| Arizona | -64% | 1971 | 15 |
| Arkansas | insufficient data | n/a | 1 |
| California | insufficient data | n/a | 1 |
| Colorado | +215% | 1970 | 59 |
| Kansas | -78% | 1970 | 26 |
| Nebraska | -65% | 1976 | 11 |
| New Mexico | +2% | 1970 | 64 |
| Oklahoma | 16× | 1969 | 30 |
| Texas | -25% | 1969 | 180 |
| Wyoming | insufficient data | n/a | 6 |
Cassin's Sparrow Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Southern Rockies / Colorado Plateau | +213% | 1976 | 31 |
| Shortgrass Prairie | +11% | 1969 | 125 |
| Central Mixed Grass Prairie | +81% | 1969 | 66 |
| Edwards Plateau | -11% | 1970 | 18 |
| Oaks and Prairies | +64% | 1969 | 40 |
| Sierra Madre Occidental | -79% | 1971 | 15 |
| Chihuahuan Desert | -56% | 1969 | 50 |
| Tamaulipan Brushlands | -54% | 1969 | 27 |
| Gulf Coastal Prairie | -67% | 1971 | 13 |
Cassin's Sparrow Conservation Status
Our route-weighted index shows it up about 61% since 1969. Grassland birds are North America's steepest-declining group, down roughly 50% since 1970 as prairie and pasture were lost.
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.