BirdAnalyst
Species · Florida · BBS 2025 Release · 1966–2024

Gull-billed Tern Population Trend in Florida

All statesWetland birds

Gull-billed Tern in Florida has edged down: down 21% on the route-weighted index since 1972.

-21%Since 1972TrendPercent 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 →
13Routes 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 →
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 Gull-billed Tern Trends in FloridaNotable 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 Gull-billed Tern in Florida. See the full index history below.

Gull-billed Tern Population Forecast in Florida

If the recent trend holds, Gull-billed Tern in Florida is projected to rise about 52% by 2028 — from 0.05 in 2023 to a central estimate of 0.08 (95% range 0.00–0.19). A 5-year backtest shows a typical error of ±60.9%, with 100% of held-out values landing inside the 95% band.

+52%Change by 2028TrendPercent 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 →
0.08Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1995% 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 →
±60.9%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, Gull-billed Tern in Florida is projected to rise about 52% by 2028 — from 0.05 in 2023 to a central estimate of 0.08 (95% range 0.00–0.19). A 5-year backtest shows a typical error of ±60.9%, with 100% of held-out values landing inside the 95% band.19662028
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 →
20240.080.000.18
20250.080.000.18
20260.080.000.18
20270.080.000.18
20280.080.000.19

Gull-billed Tern Survey Routes in Florida

Routes recording Gull-billed Tern in Florida.
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 →
Scottsmoor419681968
Lake Buffum320122012
Port St Joe 2320172017
St Vincent I320231999
Alligator Pt320172017
Ft Waltn Bch219851972
Plantation K119661966
Shawano119941994
Shawano 2120102004
Santa Rosa119991989
Wildernes Pk120092009
Sugarloaf Key119991999
Ft Lonesome120072007

Gull-billed Tern Population Trend in Other States

alabamacaliforniadelawaregeorgialouisianamarylandmississippinorth-carolinasouth-carolinatexasvirginia

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