BirdAnalyst
Species · Washington · BBS 2025 Release · 1966–2024

Northern Harrier Population Trend in Washington

All statesGeneralists

Northern Harrier in Washington has declined: down 32% on the route-weighted index since 1970.

-32%Since 1970
66Routes In State
56Years

Notable Northern Harrier Trends in Washington

No notable trend signals for Northern Harrier in Washington. See the full index history below.

Northern Harrier Population Forecast in Washington

If the recent trend holds, Northern Harrier in Washington is projected to rise about 52% by 2029 — from 0.28 in 2024 to a central estimate of 0.43 (95% range 0.07–0.78). A 5-year backtest shows a typical error of ±127.4%, with 80% of held-out values landing inside the 95% band.

+52%Change by 2029
0.43Projected 2029 index
0.07–0.7895% range
±127.4%Backtest error
19682029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20250.430.070.78
20260.430.070.78
20270.430.070.78
20280.430.070.78
20290.430.070.78

Northern Harrier Survey Routes in Washington

Routes recording Northern Harrier in Washington.
Walla Walla819931993
Pomona619991998
Wilbur520211985
Ewan420191985
Potholes420191996
Selah320122000
Arid Land Er319891988
Harrington320121973
Odessa320241993
Mesa320081994
Lake Chelan320222022
Moses Lake220211973
Mendota 2219941991
Wapato220211972
Asotin220241981
Bickleton220161984
Sulphur220191995
Nighthawk220242007
Curlew220122012
Richland220242006
Harwood219971993
Pomeroy220241998
Bay View220171999
Port Angeles120241984
Warm Beach120042004

Northern Harrier Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradodelawaregeorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.