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Species · Alabama · BBS 2025 Release · 1966–2024

Sandwich Tern Population Trend in Alabama

All statesWetland birds

Sandwich Tern in Alabama has fallen sharply: down 57% on the route-weighted index since 1984.

-57%Since 1984TrendPercent 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 →
6Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
18YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

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

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Sandwich Tern has fallen sharply in Alabama: down 57% on the route-weighted index since 1984.

Sandwich Tern Population Forecast in Alabama

If the recent trend holds, Sandwich Tern in Alabama is projected to fall about 43% by 2026 — from 0.11 in 2021 to a central estimate of 0.06 (95% range 0.00–0.33). A 5-year backtest shows a typical error of ±272.7%, with 80% of held-out values landing inside the 95% band.

-43%Change by 2026TrendPercent 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 →
0.06Projected 2026 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.3395% 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 →
±272.7%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 Alabama is projected to fall about 43% by 2026 — from 0.11 in 2021 to a central estimate of 0.06 (95% range 0.00–0.33). A 5-year backtest shows a typical error of ±272.7%, with 80% of held-out values landing inside the 95% band.19792026
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 →
20220.070.000.33
20230.070.000.33
20240.070.000.33
20250.060.000.33
20260.060.000.33

Sandwich Tern Survey Routes in Alabama

Routes recording Sandwich Tern in Alabama.
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 21020141991
Dauphin Is 3820212021
Dauphin Is419891979
Alabama Pt319991996
Chacaloochee Bay320162016
Alabama Pt 2220122012

Sandwich Tern Population Trend in Other States

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