BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Long-tailed Jaeger

StercorariidaeSeabirdsStercorarius longicaudus

Long-tailed Jaeger has surged: up 829% on the route-weighted index since 1986.

+829%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 →
28RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
38Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Long-tailed Jaeger

The Long-tailed Jaeger (Stercorarius longicaudus) is a North American member of the Skuas & Jaegers (Stercorariidae). In this analysis it is grouped with the seabirds.

Size
15.5–23.5 in long (40–60 cm) — a powerful seabird (typical for the family)
Habitat
Open ocean and coastlines, coming ashore mainly to nest in colonies.
Diet
Fish, squid and other marine animals caught at or below the surface.
Range
Recorded on 28 Breeding Bird Survey routes across 1 state, most concentrated in the BCR 2.
Family
Stercorariidae · Seabirds

Notable Long-tailed Jaeger TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Long-tailed Jaeger. See the full index history below.

Long-tailed Jaeger Population Forecast

If the recent trend holds, Long-tailed Jaeger is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.05). A 5-year backtest shows a typical error of ±58.1%, 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 →
0.02Projected 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 →
0.00–0.0595% 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 →
±58.1%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 is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.05). A 5-year backtest shows a typical error of ±58.1%, 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 →
20250.020.000.05
20260.020.000.05
20270.020.000.05
20280.020.000.05
20290.020.000.05

Where the Long-tailed Jaeger Is Detected

BBS routes recording Long-tailed Jaeger, sized by most recent count.

Long-tailed Jaeger Population Trend by State

Long-tailed Jaeger population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alaska+342%198628

Long-tailed Jaeger Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Long-tailed Jaeger population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
BCR 2+202%198914
BCR 3+11%19954
BCR 4-85%198610

Long-tailed Jaeger Conservation Status

Our route-weighted index shows it up about 828% since 1986.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.