Forster's Tern
Forster's Tern has surged: up 105% on the route-weighted index since 1968.
About the Forster's Tern
The Forster's Tern (Sterna forsteri) 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 294 Breeding Bird Survey routes across 31 states, most concentrated in the Great Basin.
- Family
- Laridae · Wetland birds
Notable Forster's Tern Trends
No notable trend signals for Forster's Tern. See the full index history below.
Forster's Tern Population Forecast
If the recent trend holds, Forster's Tern is projected to stay roughly flat through 2029, near 0.12 (95% range 0.03–0.20). A 5-year backtest shows a typical error of ±96%, with 80% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.12 | 0.03 | 0.20 |
| 2026 | 0.12 | 0.03 | 0.20 |
| 2027 | 0.12 | 0.03 | 0.20 |
| 2028 | 0.12 | 0.03 | 0.20 |
| 2029 | 0.12 | 0.03 | 0.20 |
Where the Forster's Tern Is Detected
BBS routes recording Forster's Tern, sized by most recent count.
Forster's Tern Population Trend by State
| Alabama | -33% | 1971 | 4 |
| California | -60% | 1970 | 34 |
| Colorado | -77% | 1992 | 5 |
| Delaware | 37× | 1977 | 9 |
| Florida | +111% | 1973 | 17 |
| Georgia | insufficient data | n/a | 2 |
| Idaho | -89% | 1977 | 14 |
| Illinois | insufficient data | n/a | 1 |
| Indiana | insufficient data | n/a | 1 |
| Iowa | insufficient data | n/a | 2 |
| Kansas | -58% | 1969 | 3 |
| Louisiana | -86% | 1973 | 20 |
| Maryland | -62% | 1968 | 10 |
| Michigan | insufficient data | n/a | 1 |
| Minnesota | +47% | 1975 | 24 |
| Montana | insufficient data | n/a | 4 |
| Nebraska | -13% | 1988 | 6 |
| Nevada | -74% | 1988 | 6 |
| New Jersey | -65% | 1981 | 6 |
| New York | insufficient data | n/a | 1 |
| North Carolina | -32% | 1973 | 6 |
| North Dakota | 11× | 1981 | 18 |
| Oregon | -67% | 1971 | 19 |
| South Carolina | insufficient data | n/a | 1 |
| South Dakota | -21% | 1969 | 15 |
| Texas | +152% | 1970 | 24 |
| Utah | -8% | 1992 | 8 |
| Virginia | -66% | 1970 | 6 |
| Washington | -64% | 1991 | 8 |
| Wisconsin | -24% | 1974 | 12 |
| Wyoming | -63% | 1988 | 7 |
Forster's Tern Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Great Basin | +31% | 1970 | 58 |
| Northern Rockies | -55% | 1981 | 16 |
| Prairie Potholes | +302% | 1969 | 45 |
| Boreal Hardwood Transition | -37% | 1982 | 8 |
| Central Mixed Grass Prairie | -46% | 1969 | 8 |
| Prairie Hardwood Transition | +70% | 1975 | 16 |
| Southeastern Coastal Plain | -74% | 1969 | 22 |
| New England / Mid-Atlantic Coast | +276% | 1968 | 31 |
| Peninsular Florida | +34% | 1973 | 9 |
| Coastal California | -60% | 1970 | 18 |
| Gulf Coastal Prairie | +136% | 1970 | 34 |
Forster's Tern Conservation Status
Our route-weighted index shows it up about 105% 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.