Black Tern Population Analysis
Black Tern has fallen sharply: down 51% on the route-weighted index since 1968.
About the Black Tern
The Black Tern (Chlidonias niger) 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 306 Breeding Bird Survey routes across 24 states, most concentrated in the Prairie Potholes.
- Family
- Laridae · Wetland birds
Notable Black Tern TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →
Black Tern has fallen sharply in surveyed states: down 51% on the route-weighted index since 1968.
Black Tern Population Forecast
If the recent trend holds, Black Tern is projected to stay roughly flat through 2030, near 0.16 (95% range 0.00–0.36). A 5-year backtest shows a typical error of ±24.2%, with 100% of held-out values landing inside the 95% band.
Where the Black Tern Is Detected
BBS routes recording Black Tern, sized by most recent count.
Black Tern Population Trend by State
Black Tern Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
Black Tern Conservation Status
Our route-weighted index shows it down about 51% since 1968.
Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.