Northern Harrier
Northern Harrier has held roughly steady: up 9% on the route-weighted index since 1968.
About the Northern Harrier
The Northern Harrier (Circus hudsonius) is a North American member of the Hawks, Eagles & Kites (Accipitridae). In this analysis it is grouped with the birds of prey.
- Size
- 17.5–39.5 in long (45–100 cm) — a medium to large raptor (typical for the family)
- Habitat
- Open country, woodlands, cliffs and wetlands, hunting from the air or a high perch.
- Diet
- Live prey — small mammals, birds, reptiles, fish and large insects (carrion for vultures).
- Range
- Recorded on 1,635 Breeding Bird Survey routes across 45 states, most concentrated in the Great Basin.
- Family
- Accipitridae · Birds of prey
Notable Northern Harrier Trends
No notable trend signals for Northern Harrier. See the full index history below.
Northern Harrier Population Forecast
If the recent trend holds, Northern Harrier is projected to stay roughly flat through 2029, near 0.21 (95% range 0.12–0.30). A 5-year backtest shows a typical error of ±49.5%, with 60% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.21 | 0.12 | 0.30 |
| 2026 | 0.21 | 0.12 | 0.30 |
| 2027 | 0.21 | 0.12 | 0.30 |
| 2028 | 0.21 | 0.12 | 0.30 |
| 2029 | 0.21 | 0.12 | 0.30 |
Where the Northern Harrier Is Detected
BBS routes recording Northern Harrier, sized by most recent count.
Northern Harrier Population Trend by State
| Alabama | insufficient data | n/a | 1 |
| Alaska | -66% | 1986 | 51 |
| Arizona | insufficient data | n/a | 8 |
| Arkansas | insufficient data | n/a | 1 |
| California | -71% | 1970 | 113 |
| Colorado | -83% | 1970 | 85 |
| Delaware | +26% | 1979 | 6 |
| Georgia | insufficient data | n/a | 1 |
| Idaho | -43% | 1970 | 47 |
| Illinois | -70% | 1972 | 53 |
| Indiana | -65% | 1971 | 23 |
| Iowa | +14% | 1982 | 19 |
| Kansas | -96% | 1969 | 46 |
| Kentucky | insufficient data | n/a | 5 |
| Louisiana | insufficient data | n/a | 1 |
| Maine | -56% | 1975 | 26 |
| Maryland | -26% | 1972 | 17 |
| Massachusetts | insufficient data | n/a | 5 |
| Michigan | -83% | 1968 | 61 |
| Minnesota | -64% | 1969 | 74 |
| Missouri | -69% | 1973 | 17 |
| Montana | -11% | 1970 | 89 |
| Nebraska | -71% | 1969 | 48 |
| Nevada | +187% | 1970 | 38 |
| New Hampshire | insufficient data | n/a | 5 |
| New Jersey | -13% | 1987 | 4 |
| New Mexico | -76% | 1973 | 29 |
| New York | +113% | 1969 | 57 |
| North Carolina | insufficient data | n/a | 3 |
| North Dakota | -18% | 1969 | 50 |
| Ohio | +7% | 1971 | 31 |
| Oklahoma | -94% | 1969 | 36 |
| Oregon | +189% | 1970 | 66 |
| Pennsylvania | -29% | 1971 | 41 |
| Rhode Island | insufficient data | n/a | 1 |
| South Dakota | -49% | 1969 | 50 |
| Tennessee | insufficient data | n/a | 1 |
| Texas | -79% | 1969 | 59 |
| Utah | -30% | 1970 | 82 |
| Vermont | -5% | 1975 | 9 |
| Virginia | -18% | 1984 | 11 |
| Washington | -32% | 1970 | 66 |
| West Virginia | insufficient data | n/a | 3 |
| Wisconsin | -52% | 1968 | 83 |
| Wyoming | -19% | 1970 | 113 |
Northern Harrier Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| BCR 2 | -61% | 1996 | 13 |
| BCR 4 | -66% | 1987 | 30 |
| Northern Pacific Rainforest | +94% | 1973 | 43 |
| Great Basin | +10% | 1970 | 214 |
| Northern Rockies | +2% | 1970 | 137 |
| Prairie Potholes | -6% | 1969 | 110 |
| Boreal Hardwood Transition | -42% | 1968 | 87 |
| Lower Great Lakes / St. Lawrence Plain | +74% | 1969 | 50 |
| Atlantic Northern Forest | -52% | 1974 | 42 |
| Sierra Nevada | +10% | 1998 | 9 |
| Southern Rockies / Colorado Plateau | -58% | 1970 | 88 |
| Badlands and Prairies | -44% | 1969 | 115 |
| Shortgrass Prairie | -76% | 1969 | 109 |
| Central Mixed Grass Prairie | -96% | 1969 | 77 |
| Oaks and Prairies | -8% | 1969 | 18 |
| Eastern Tallgrass Prairie | -82% | 1968 | 131 |
| Prairie Hardwood Transition | -64% | 1968 | 108 |
| Central Hardwoods | -22% | 1973 | 20 |
| Appalachian Mountains | -49% | 1969 | 60 |
| Piedmont | -52% | 1985 | 11 |
| New England / Mid-Atlantic Coast | -66% | 1972 | 35 |
| Coastal California | -75% | 1970 | 65 |
| Sonoran and Mojave Deserts | +49% | 1975 | 19 |
| Chihuahuan Desert | -76% | 1973 | 15 |
Northern Harrier Conservation Status
Our route-weighted index shows it up about 9% since 1968.
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.