BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Swainson's Hawk

AccipitridaeBirds of preyButeo swainsoni

Swainson's Hawk has surged: up 172% on the route-weighted index since 1969.

+172%Since 1969TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
1,108RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
57Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Swainson's Hawk

The Swainson's Hawk (Buteo swainsoni) 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 1,108 Breeding Bird Survey routes across 24 states, most concentrated in the Great Basin.
Family
Accipitridae · Birds of prey

Notable Swainson's Hawk TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Swainson's Hawk has surged in surveyed states: up 172% on the route-weighted index since 1969.

Swainson's Hawk Population Forecast

If the recent trend holds, Swainson's Hawk is projected to rise about 24% by 2029 — from 0.39 in 2024 to a central estimate of 0.49 (95% range 0.40–0.57). A 5-year backtest shows a typical error of ±8.9%, with 100% of held-out values landing inside the 95% band.

+24%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.49Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.40–0.5795% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±8.9%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Swainson's Hawk is projected to rise about 24% by 2029 — from 0.39 in 2024 to a central estimate of 0.49 (95% range 0.40–0.57). A 5-year backtest shows a typical error of ±8.9%, with 100% of held-out values landing inside the 95% band.19672029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.460.370.55
20260.470.380.56
20270.470.390.56
20280.480.390.57
20290.490.400.57

Where the Swainson's Hawk Is Detected

BBS routes recording Swainson's Hawk, sized by most recent count.

Swainson's Hawk Population Trend by State

Swainson's Hawk population trend by state.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Arizona+616%197030
Arkansasinsufficient datan/a4
California24×197451
Colorado+44%1970102
Idaho+622%197237
Illinoisinsufficient datan/a1
Iowainsufficient datan/a2
Kansas-54%196952
Louisiana+37%200313
Minnesota-20%198022
Missouriinsufficient datan/a6
Montana+644%197077
Nebraska+70%196950
Nevada+246%197029
New Mexico+69%197060
North Dakota+114%196948
Oklahoma+122%196944
Oregon+77%197048
South Dakota+16%196950
Texas+53%1969182
Utah-41%197260
Washington+208%197140
Wisconsininsufficient datan/a1
Wyoming+171%197099

Swainson's Hawk Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Swainson's Hawk population trend by Bird Conservation Region.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Great Basin+369%1970173
Northern Rockies+424%1971116
Prairie Potholes+178%196993
Southern Rockies / Colorado Plateau+141%1970104
Badlands and Prairies+47%1969104
Shortgrass Prairie+166%1969134
Central Mixed Grass Prairie-65%1969108
Edwards Plateau-28%197513
Oaks and Prairies-9%196951
Eastern Tallgrass Prairie-83%196923
Coastal California27×197525
Sonoran and Mojave Deserts-54%197515
Sierra Madre Occidental+527%197119
Chihuahuan Desert+18%197049
Tamaulipan Brushlands-41%196927
Gulf Coastal Prairie+8%198428

Swainson's Hawk Conservation Status

Our route-weighted index shows it up about 172% since 1969.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.