Parasitic Jaeger
Parasitic Jaeger has fallen sharply: down 73% on the route-weighted index since 1985.
About the Parasitic Jaeger
The Parasitic Jaeger (Stercorarius parasiticus) 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 20 Breeding Bird Survey routes across 1 state, most concentrated in the BCR 2.
- Family
- Stercorariidae · Seabirds
Notable Parasitic Jaeger Trends
No notable trend signals for Parasitic Jaeger. See the full index history below.
Parasitic Jaeger Population Forecast
If the recent trend holds, Parasitic Jaeger is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.00). A 5-year backtest shows a typical error of ±55.3%, with 100% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.00 | 0.00 | 0.01 |
| 2026 | 0.00 | 0.00 | 0.01 |
| 2027 | 0.00 | 0.00 | 0.01 |
| 2028 | 0.00 | 0.00 | 0.01 |
| 2029 | 0.00 | 0.00 | 0.00 |
Where the Parasitic Jaeger Is Detected
BBS routes recording Parasitic Jaeger, sized by most recent count.
Parasitic Jaeger Population Trend by State
| Alaska | -88% | 1985 | 20 |
Parasitic Jaeger Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| BCR 2 | -43% | 1991 | 13 |
Parasitic Jaeger Conservation Status
Our route-weighted index shows it down about 73% since 1985.
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.