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Species · Alaska · BBS 2025 Release · 1966–2024

Rock Ptarmigan Population Trend in Alaska

All statesGeneralists

Rock Ptarmigan in Alaska has collapsed: down 86% on the route-weighted index since 1984.

-86%Since 1984TrendPercent 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 →
12Routes 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 →
37YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Rock Ptarmigan 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 declinecomputed 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 →

Rock Ptarmigan has collapsed in Alaska: down 86% on the route-weighted index since 1984.

Rock Ptarmigan Population Forecast in Alaska

If the recent trend holds, Rock Ptarmigan in Alaska is projected to fall about 100% by 2029 — from 0.18 in 2024 to a central estimate of 0.00 (95% range 0.00–0.45). A 5-year backtest shows a typical error of ±347.8%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.4595% 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 →
±347.8%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, Rock Ptarmigan in Alaska is projected to fall about 100% by 2029 — from 0.18 in 2024 to a central estimate of 0.00 (95% range 0.00–0.45). A 5-year backtest shows a typical error of ±347.8%, with 100% of held-out values landing inside the 95% band.19822029
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 →
20250.000.000.45
20260.000.000.45
20270.000.000.45
20280.000.000.45
20290.000.000.45

Rock Ptarmigan Survey Routes in Alaska

Routes recording Rock Ptarmigan 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 →
Adak1820011983
Galbraith L.820242006
Skagway219991999
Teller220241993
Chiniak120082008
Nome120121996
Salmon Lake120241996
Toklat120121982
Savage120122012
Council120151996
Happy Valley120242016
Cold Bay120222001

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