Sandwich Tern
Sandwich Tern has surged: up 123% on the route-weighted index since 1979.
About the Sandwich Tern
The Sandwich Tern (Thalasseus sandvicensis) is a North American member of the Gulls, Terns & Skimmers (Laridae). In this analysis it is grouped with the wetland birds.
- Size
- 8.5–31.5 in long (22–80 cm) — a long-winged waterbird (typical for the family)
- Habitat
- Marshes, ponds, lakeshores and other freshwater wetlands.
- Diet
- Aquatic invertebrates, small fish, frogs and plant matter.
- Range
- Recorded on 19 Breeding Bird Survey routes across 6 states, most concentrated in the Southeastern Coastal Plain.
- Family
- Laridae · Wetland birds
Notable Sandwich Tern Trends
No notable trend signals for Sandwich Tern. See the full index history below.
Sandwich Tern Population Forecast
If the recent trend holds, Sandwich Tern is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.03). A 5-year backtest shows a typical error of ±67.8%, with 40% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.01 | 0.00 | 0.03 |
| 2026 | 0.01 | 0.00 | 0.03 |
| 2027 | 0.01 | 0.00 | 0.03 |
| 2028 | 0.01 | 0.00 | 0.03 |
| 2029 | 0.01 | 0.00 | 0.03 |
Where the Sandwich Tern Is Detected
BBS routes recording Sandwich Tern, sized by most recent count.
Sandwich Tern Population Trend by State
| Alabama | -57% | 1984 | 6 |
| Florida | insufficient data | n/a | 6 |
| Louisiana | insufficient data | n/a | 1 |
| North Carolina | insufficient data | n/a | 2 |
| Texas | insufficient data | n/a | 3 |
| Virginia | insufficient data | n/a | 1 |
Sandwich Tern Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Southeastern Coastal Plain | -36% | 1979 | 12 |
| Gulf Coastal Prairie | +469% | 2010 | 4 |
Sandwich Tern Conservation Status
Our route-weighted index shows it up about 123% since 1979.
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.