BirdAnalyst
Species · BCR 10 · BBS 2026 Release · 1966–2025

Swainson's Hawk In Northern Rockies

All regionsNorthern RockiesBirds of prey

Swainson's Hawk in Northern Rockies has surged: up 421% on the route-weighted index since 1971.

+421%Since 1971TrendPercent 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 →
119Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 Northern Rockies: up 421% on the route-weighted index since 1971.

Swainson's Hawk In Northern Rockies Population Forecast

If the recent trend holds, Swainson's Hawk in Northern Rockies is projected to stay roughly flat through 2030, near 0.38 (95% range 0.18–0.58). A 5-year backtest shows a typical error of ±18.7%, with 80% of held-out values landing inside the 95% band.

+0%Change by 2030TrendPercent 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 →
0.38Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.18–0.5895% 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 →
±18.7%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 in Northern Rockies is projected to stay roughly flat through 2030, near 0.38 (95% range 0.18–0.58). A 5-year backtest shows a typical error of ±18.7%, with 80% of held-out values landing inside the 95% band.19692030
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 →
20260.360.170.56
20270.370.170.57
20280.370.180.57
20290.380.180.57
20300.380.180.58

Routes In Northern Rockies

Routes recording Swainson's Hawk in Northern Rockies.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
HarmonyWYOMING82023
BoulderMONTANA62025
Church HillMONTANA52025
BridgeportOREGON52021
Elk HornWYOMING52018
WamsutterWYOMING42025
SeedskadeeWYOMING42016
Crane CreekIDAHO32019
Sawtooth City 2IDAHO32023
FontenelleWYOMING32025
EtheteWYOMING32023
BoulderWYOMING32025
Mtn ViewWYOMING31980
WalcottWYOMING32025
Great DivideCOLORADO22025
CascadeIDAHO21982
LaurelMONTANA22017
BeaverheadMONTANA22025
St. Mary 2MONTANA22025
GlenMONTANA22025
Wolf CreekMONTANA22025
RaynesfordMONTANA22024
Brunzell SloughMONTANA22025
Hebgen LakeMONTANA22024
Fort LoganMONTANA22024

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.