BirdAnalyst
Species · BCR 31 · BBS 2025 Release · 1966–2024

Forster's Tern In Peninsular Florida

All regionsPeninsular FloridaWetland birds

Forster's Tern in Peninsular Florida has increased: up 34% on the route-weighted index since 1973.

+34%Since 1973TrendPercent 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 →
9Routes 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 →
22YearsYears 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 Forster's Tern in Peninsular Florida. See the full index history below.

Forster's Tern In Peninsular Florida Population Forecast

If the recent trend holds, Forster's Tern in Peninsular Florida is projected to fall about 62% by 2029 — from 0.32 in 2024 to a central estimate of 0.12 (95% range 0.00–0.49). A 5-year backtest shows a typical error of ±108.3%, with 80% of held-out values landing inside the 95% band.

-62%Change 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 →
0.12Projected 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 →
0.00–0.4995% 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 →
±108.3%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, Forster's Tern in Peninsular Florida is projected to fall about 62% by 2029 — from 0.32 in 2024 to a central estimate of 0.12 (95% range 0.00–0.49). A 5-year backtest shows a typical error of ±108.3%, with 80% of held-out values landing inside the 95% band.19682029
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 →
20250.130.000.50
20260.120.000.50
20270.120.000.50
20280.120.000.50
20290.120.000.49

Routes In Peninsular Florida

Routes recording Forster's Tern in Peninsular 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 →
ScottsmoorFLORIDA122024
MabelFLORIDA81998
St AugustineFLORIDA22021
ChildsFLORIDA11988
AripekaFLORIDA12004
CroomFLORIDA11998
Merritt IslFLORIDA12003
Ridge HarborFLORIDA12002
Merritt Island 2FLORIDA12014

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