BirdAnalyst
Species · BCR 27 · BBS 2026 Release · 1966–2025

Caspian Tern In Southeastern Coastal Plain

All regionsSoutheastern Coastal PlainWetland birds

Caspian Tern in Southeastern Coastal Plain has declined: down 28% on the route-weighted index since 1970.

-28%Since 1970TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
12Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
41YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Caspian Tern in Southeastern Coastal Plain. See the full index history below.

Caspian Tern In Southeastern Coastal Plain Population Forecast

If the recent trend holds, Caspian Tern in Southeastern Coastal Plain is projected to stay roughly flat through 2030, near 0.03 (95% range 0.00–0.07). A 5-year backtest shows a typical error of ±16.3%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2030TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.03Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0795% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±16.3%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Caspian Tern in Southeastern Coastal Plain is projected to stay roughly flat through 2030, near 0.03 (95% range 0.00–0.07). A 5-year backtest shows a typical error of ±16.3%, with 100% of held-out values landing inside the 95% band.19662030
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20260.030.000.08
20270.030.000.07
20280.030.000.07
20290.030.000.07
20300.030.000.07

Routes In Southeastern Coastal Plain

Routes recording Caspian Tern in Southeastern Coastal Plain.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
St. ElmoALABAMA42025
Dauphin Is 2ALABAMA32019
Alabama PtALABAMA22000
Ft Waltn BchFLORIDA22002
Johns IsleSOUTH-CAROLINA21968
Dauphin IsALABAMA11990
Port St JoeFLORIDA12008
Ft GadsdenFLORIDA11979
Santa RosaFLORIDA11998
St Vincent IFLORIDA12025
MerrimonNORTH-CAROLINA12002
Kiawah IslandSOUTH-CAROLINA11999

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.