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Species · BCR 4 · BBS 2026 Release · 1966–2025

Long-tailed Jaeger In BCR 4

All regionsBCR 4Seabirds

Long-tailed Jaeger in BCR 4 has collapsed: down 81% on the route-weighted index since 1986.

-81%Since 1986TrendPercent 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 →
11Routes 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 →
27YearsYears 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 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 →

Long-tailed Jaeger has collapsed in BCR 4: down 81% on the route-weighted index since 1986.

Long-tailed Jaeger In BCR 4 Population Forecast

If the recent trend holds, Long-tailed Jaeger in BCR 4 is projected to fall about 100% by 2030 — from 0.08 in 2025 to a central estimate of 0.00 (95% range 0.00–0.21). A 5-year backtest shows a typical error of ±136.3%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.2195% 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 →
±136.3%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, Long-tailed Jaeger in BCR 4 is projected to fall about 100% by 2030 — from 0.08 in 2025 to a central estimate of 0.00 (95% range 0.00–0.21). A 5-year backtest shows a typical error of ±136.3%, with 100% of held-out values landing inside the 95% band.19822030
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 →
20260.000.000.21
20270.000.000.21
20280.000.000.21
20290.000.000.21
20300.000.000.21

Routes In BCR 4

Routes recording Long-tailed Jaeger in BCR 4.
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 →
Mud RiverALASKA61997
Kobuk River (Short)ALASKA51991
SavageALASKA32025
Kanuti LakeALASKA22006
MaclarenALASKA12022
MonahanALASKA12012
ToklatALASKA12010
Chena Hot SpALASKA11986
KachemakALASKA12018
Caribou Mtn.ALASKA12007
Paxson LakeALASKA11997

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