Gull-billed Tern
Gull-billed Tern has surged: up 101% on the route-weighted index since 1968.
About the Gull-billed Tern
The Gull-billed Tern (Gelochelidon nilotica) 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 56 Breeding Bird Survey routes across 12 states, most concentrated in the Gulf Coastal Prairie.
- Family
- Laridae · Wetland birds
Notable Gull-billed Tern Trends
No notable trend signals for Gull-billed Tern. See the full index history below.
Gull-billed Tern Population Forecast
If the recent trend holds, Gull-billed Tern is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.04). A 5-year backtest shows a typical error of ±221.4%, with 80% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.02 | 0.00 | 0.04 |
| 2026 | 0.02 | 0.00 | 0.04 |
| 2027 | 0.02 | 0.00 | 0.04 |
| 2028 | 0.02 | 0.00 | 0.04 |
| 2029 | 0.02 | 0.00 | 0.04 |
Where the Gull-billed Tern Is Detected
BBS routes recording Gull-billed Tern, sized by most recent count.
Gull-billed Tern Population Trend by State
| Alabama | -94% | 1985 | 4 |
| California | insufficient data | n/a | 1 |
| Delaware | insufficient data | n/a | 1 |
| Florida | -21% | 1972 | 13 |
| Georgia | insufficient data | n/a | 1 |
| Louisiana | -18% | 1997 | 5 |
| Maryland | insufficient data | n/a | 2 |
| Mississippi | insufficient data | n/a | 1 |
| North Carolina | -90% | 1968 | 5 |
| South Carolina | insufficient data | n/a | 2 |
| Texas | +63% | 1971 | 20 |
| Virginia | insufficient data | n/a | 1 |
Gull-billed Tern Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Southeastern Coastal Plain | -75% | 1968 | 18 |
| Tamaulipan Brushlands | +13% | 1985 | 4 |
| Gulf Coastal Prairie | +75% | 1971 | 20 |
Gull-billed Tern Conservation Status
Our route-weighted index shows it up about 101% since 1968.
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.