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

Caspian Tern Population Trend in Florida

All statesWetland birds

Caspian Tern in Florida has edged down: down 12% on the route-weighted index since 1976.

-12%Since 1976TrendPercent 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 →
22Routes 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 →
39YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Caspian 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 Caspian Tern in Florida. See the full index history below.

Caspian Tern Population Forecast in Florida

If the recent trend holds, Caspian Tern in Florida is projected to stay roughly flat through 2029, near 0.09 (95% range 0.00–0.24). A 5-year backtest shows a typical error of ±182.6%, 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 →
0.09Projected 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 →
0.00–0.2495% 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 →
±182.6%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 Florida is projected to stay roughly flat through 2029, near 0.09 (95% range 0.00–0.24). A 5-year backtest shows a typical error of ±182.6%, 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 →
20250.090.000.24
20260.090.000.24
20270.090.000.24
20280.090.000.24
20290.090.000.24

Caspian Tern Survey Routes in Florida

Routes recording Caspian 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 →
Scottsmoor1020211977
Sandy920082008
Tamiami619711970
Pleasant Gr620092006
Merritt Isl320051991
Shawano 2320072007
Ft Waltn Bch220022002
Flamingo220002000
St Vincent I220191997
Ft Lonesome220242007
Port St Joe120081998
Ft Gadsden119791976
San Antonio119871987
Ridge Harbor120052005
Merritt Island 2120142014
Indiantown120041976
Plantation K119701970
Andytown119811981
Pleasant Grove 2120212010
Santa Rosa119981988
Shawano120012001
Clewiston120192019

Caspian Tern Population Trend in Other States

alabamaalaskacaliforniadelawareidahoillinoisindianalouisianamarylandmichiganminnesotamontananevadanorth-carolinanorth-dakotaoregonsouth-carolinatexasutahvermontvirginiawashingtonwisconsinwyoming

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