BirdAnalyst
Species · BCR 27 · BBS 2025 Release · 1966–2024

Sandwich Tern In Southeastern Coastal Plain

All regionsSoutheastern Coastal PlainWetland birds

Sandwich Tern in Southeastern Coastal Plain has declined: down 36% on the route-weighted index since 1979.

-36%Since 1979TrendPercent 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 →
27YearsYears 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 Sandwich Tern in Southeastern Coastal Plain. See the full index history below.

Sandwich Tern In Southeastern Coastal Plain Population Forecast

If the recent trend holds, Sandwich Tern in Southeastern Coastal Plain is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.11). A 5-year backtest shows a typical error of ±248.5%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2029TrendPercent 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 →
0.02Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1195% 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 →
±248.5%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, Sandwich Tern in Southeastern Coastal Plain is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.11). A 5-year backtest shows a typical error of ±248.5%, with 100% of held-out values landing inside the 95% band.19702029
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 →
20250.030.000.11
20260.030.000.11
20270.030.000.11
20280.020.000.11
20290.020.000.11

Routes In Southeastern Coastal Plain

Routes recording Sandwich 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 →
Dauphin Is 2ALABAMA102014
Dauphin Is 3ALABAMA82021
Dauphin IsALABAMA41989
Alabama PtALABAMA31999
Chacaloochee BayALABAMA32016
Myrtle GroveNORTH-CAROLINA32024
Alabama Pt 2ALABAMA22012
St Vincent IFLORIDA22024
Ft Waltn BchFLORIDA11999
Port St JoeFLORIDA11985
Santa RosaFLORIDA11988
MerrimonNORTH-CAROLINA12021

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.