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

Parasitic Jaeger Population Trend in Alaska

All statesGeneralists

Parasitic Jaeger in Alaska has collapsed: down 88% on the route-weighted index since 1985.

-88%Since 1985TrendPercent 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 →
20Routes 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 →
39YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Parasitic Jaeger 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 →

Parasitic Jaeger has collapsed in Alaska: down 88% on the route-weighted index since 1985.

Parasitic Jaeger Population Forecast in Alaska

If the recent trend holds, Parasitic Jaeger in Alaska is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±252.5%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00–0.2795% 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 →
±252.5%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, Parasitic Jaeger in Alaska is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±252.5%, with 100% of held-out values landing inside the 95% band.19832029
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 →
20250.000.000.27
20260.000.000.27
20270.000.000.27
20280.000.000.27
20290.000.000.27

Parasitic Jaeger Survey Routes in Alaska

Routes recording Parasitic Jaeger 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 →
Copper River520112003
Utqiagvik320232022
Tupuknuk319951995
King Salmon320231995
Kotzebue (Short)319861986
Teller220171993
Kotzebue220192002
Cold Bay220241995
Adak220011983
Chiniak119891989
Cape Nome120181993
Council120091996
Galbraith L.120222022
Kalifonsky120152015
Nome120121995
Salmon Lake119981997
St. Mary'S120121994
Red Dog120232023
Cold Bay (Short)119921991
Yakutat119991994

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