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

Rough-legged Hawk Population Trend in Alaska

All statesGeneralists

Rough-legged Hawk in Alaska has surged: up 121% on the route-weighted index since 1991.

+121%Since 1991TrendPercent 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 →
26Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
35YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Rough-legged Hawk Trends in AlaskaNotable 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 →

Rough-legged Hawk has surged in Alaska: up 121% on the route-weighted index since 1991.

Rough-legged Hawk Population Forecast in Alaska

If the recent trend holds, Rough-legged Hawk in Alaska is projected to fall about 14% by 2029 — from 0.09 in 2024 to a central estimate of 0.08 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±86%, with 100% of held-out values landing inside the 95% band.

-14%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 →
0.08Projected 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 →
0.00–0.1595% 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 →
±86%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, Rough-legged Hawk in Alaska is projected to fall about 14% by 2029 — from 0.09 in 2024 to a central estimate of 0.08 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±86%, with 100% of held-out values landing inside the 95% band.19872029
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 →
20250.080.000.15
20260.080.000.15
20270.080.000.15
20280.080.000.15
20290.080.000.15

Rough-legged Hawk Survey Routes in Alaska

Routes recording Rough-legged Hawk in Alaska.
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 →
Unalakleet River320172006
Chatanika R220082008
Happy Valley220241993
Goodnews Bay220032000
Chiniak119981990
Kuskulana120242024
Coldfoot120171998
Council120151994
Galbraith L.120131999
Hather Creek120111997
Kanuti Canyn119931993
Koyukuk Riv.119931993
Cottonwood119871987
Mud River120212015
Nome120231997
Salmon Lake120231994
Teller120241993
Delta120012001
Anvik River120231998
Gweek River119981998
Sourdough120232023
Red Dog120241995
Cold Bay120241996
Bear Creek119911991
Savage120172017

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