Henslow's Sparrow
Henslow's Sparrow has collapsed: down 82% on the route-weighted index since 1968.
About the Henslow's Sparrow
The Henslow's Sparrow (Centronyx henslowii) 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 436 Breeding Bird Survey routes across 22 states, most concentrated in the Eastern Tallgrass Prairie.
- Family
- Passerellidae · Grassland birds
Notable Henslow's Sparrow Trends
Henslow's Sparrow has collapsed in surveyed states: down 82% on the route-weighted index since 1968.
Henslow's Sparrow Population Forecast
If the recent trend holds, Henslow's Sparrow is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.05). A 5-year backtest shows a typical error of ±49.1%, with 100% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.01 | 0.00 | 0.05 |
| 2026 | 0.01 | 0.00 | 0.05 |
| 2027 | 0.01 | 0.00 | 0.05 |
| 2028 | 0.01 | 0.00 | 0.05 |
| 2029 | 0.01 | 0.00 | 0.05 |
Where the Henslow's Sparrow Is Detected
BBS routes recording Henslow's Sparrow, sized by most recent count.
Henslow's Sparrow Population Trend by State
| Delaware | insufficient data | n/a | 3 |
| Illinois | +51% | 1973 | 33 |
| Indiana | -73% | 1968 | 32 |
| Iowa | +293% | 1978 | 16 |
| Kansas | -39% | 1989 | 15 |
| Kentucky | +141% | 1973 | 21 |
| Maryland | -66% | 1969 | 12 |
| Michigan | -95% | 1968 | 36 |
| Minnesota | -61% | 1982 | 17 |
| Missouri | +370% | 1974 | 40 |
| Nebraska | insufficient data | n/a | 2 |
| New York | -82% | 1968 | 42 |
| North Carolina | -68% | 1985 | 6 |
| North Dakota | insufficient data | n/a | 2 |
| Ohio | -57% | 1968 | 38 |
| Oklahoma | -65% | 1995 | 4 |
| Pennsylvania | -94% | 1968 | 36 |
| South Dakota | insufficient data | n/a | 2 |
| Vermont | insufficient data | n/a | 2 |
| Virginia | insufficient data | n/a | 3 |
| West Virginia | -88% | 1972 | 9 |
| Wisconsin | -84% | 1968 | 65 |
Henslow's Sparrow Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Boreal Hardwood Transition | -39% | 1971 | 22 |
| Lower Great Lakes / St. Lawrence Plain | -95% | 1968 | 42 |
| Central Mixed Grass Prairie | -17% | 1999 | 5 |
| Eastern Tallgrass Prairie | +71% | 1968 | 114 |
| Prairie Hardwood Transition | -92% | 1968 | 97 |
| Central Hardwoods | -7% | 1968 | 51 |
| Southeastern Coastal Plain | -87% | 1985 | 7 |
| Appalachian Mountains | -95% | 1968 | 69 |
Henslow's Sparrow Conservation Status
Our route-weighted index shows it down about 82% since 1968. 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.