Common Tern
Common Tern has collapsed: down 97% on the route-weighted index since 1968.
About the Common Tern
The Common Tern (Sterna hirundo) 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 119 Breeding Bird Survey routes across 27 states, most concentrated in the New England / Mid-Atlantic Coast.
- Family
- Laridae · Wetland birds
Notable Common Tern Trends
Common Tern has collapsed in surveyed states: down 97% on the route-weighted index since 1968.
Common Tern Population Forecast
If the recent trend holds, Common Tern is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±1414.8%, with 100% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.00 | 0.00 | 0.12 |
| 2026 | 0.00 | 0.00 | 0.12 |
| 2027 | 0.00 | 0.00 | 0.12 |
| 2028 | 0.00 | 0.00 | 0.12 |
| 2029 | 0.00 | 0.00 | 0.12 |
Where the Common Tern Is Detected
BBS routes recording Common Tern, sized by most recent count.
Common Tern Population Trend by State
| Alabama | insufficient data | n/a | 2 |
| Alaska | insufficient data | n/a | 1 |
| Connecticut | insufficient data | n/a | 1 |
| Delaware | -90% | 1968 | 5 |
| Florida | insufficient data | n/a | 2 |
| Idaho | insufficient data | n/a | 1 |
| Indiana | insufficient data | n/a | 3 |
| Louisiana | -63% | 1979 | 5 |
| Maine | -62% | 1968 | 6 |
| Maryland | -54% | 1968 | 7 |
| Massachusetts | -75% | 1969 | 6 |
| Michigan | insufficient data | n/a | 4 |
| Minnesota | insufficient data | n/a | 8 |
| Montana | -83% | 1976 | 10 |
| New Jersey | -87% | 1981 | 5 |
| New York | -97% | 1968 | 9 |
| North Carolina | -75% | 1969 | 5 |
| North Dakota | +174% | 1979 | 17 |
| Ohio | insufficient data | n/a | 2 |
| Rhode Island | insufficient data | n/a | 1 |
| South Dakota | insufficient data | n/a | 2 |
| Texas | insufficient data | n/a | 6 |
| Vermont | insufficient data | n/a | 1 |
| Virginia | insufficient data | n/a | 4 |
| Washington | insufficient data | n/a | 1 |
| Wisconsin | -86% | 1969 | 3 |
| Wyoming | insufficient data | n/a | 2 |
Common Tern Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Prairie Potholes | +86% | 1980 | 25 |
| Boreal Hardwood Transition | -89% | 1969 | 8 |
| Lower Great Lakes / St. Lawrence Plain | -64% | 1975 | 6 |
| Atlantic Northern Forest | +304% | 1984 | 5 |
| Prairie Hardwood Transition | -90% | 1970 | 8 |
| Southeastern Coastal Plain | +5% | 1969 | 9 |
| New England / Mid-Atlantic Coast | -96% | 1968 | 35 |
| Gulf Coastal Prairie | +24% | 1976 | 11 |
Common Tern Conservation Status
Our route-weighted index shows it down about 97% 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.