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

Least Tern In Peninsular Florida

All regionsPeninsular FloridaWetland birds

Least Tern in Peninsular Florida has collapsed: down 98% on the route-weighted index since 1968.

-98%Since 1968TrendPercent 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 →
39Routes 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 →
58YearsYears 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 →

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 →

Least Tern has collapsed in Peninsular Florida: down 98% on the route-weighted index since 1968.

Least Tern In Peninsular Florida Population Forecast

If the recent trend holds, Least Tern in Peninsular Florida is projected to fall about 100% by 2029 — from 0.13 in 2024 to a central estimate of 0.00 (95% range 0.00–2.5). A 5-year backtest shows a typical error of ±1470.1%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–2.595% 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 →
±1470.1%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, Least Tern in Peninsular Florida is projected to fall about 100% by 2029 — from 0.13 in 2024 to a central estimate of 0.00 (95% range 0.00–2.5). A 5-year backtest shows a typical error of ±1470.1%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.000.002.5
20260.000.002.5
20270.000.002.5
20280.000.002.5
20290.000.002.5

Routes In Peninsular Florida

Routes recording Least 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 →
St LucieFLORIDA172002
Key LargoFLORIDA161991
Merritt IslFLORIDA152008
Key WestFLORIDA81987
Citrus ParkFLORIDA82009
Boca RatonFLORIDA61994
ScottsmoorFLORIDA52024
Plantation KFLORIDA52004
IndiantownFLORIDA42017
SandyFLORIDA42007
HomesteadFLORIDA32007
Indiantown 2FLORIDA32022
Sugarloaf Key 2FLORIDA32018
Dale MabryFLORIDA21988
BelmoreFLORIDA21972
MabelFLORIDA21968
ChildsFLORIDA21977
SalvistaFLORIDA21978
BrowardFLORIDA21973
Winter GardnFLORIDA22008
DavieFLORIDA22011
Weaver StnFLORIDA21995
Punta GordaFLORIDA22014
Vero BeachFLORIDA22018
Sugarloaf KeyFLORIDA22003

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