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

Royal Tern In Peninsular Florida

All regionsPeninsular FloridaWetland birds

Royal Tern in Peninsular Florida has collapsed: down 89% on the route-weighted index since 1968.

-89%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 →
18Routes 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 →
53YearsYears 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 →

Royal Tern has collapsed in Peninsular Florida: down 89% on the route-weighted index since 1968.

Royal Tern In Peninsular Florida Population Forecast

If the recent trend holds, Royal 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 0.00–0.93). A 5-year backtest shows a typical error of ±187.6%, 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 →
0.00–0.9395% 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 →
±187.6%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, Royal 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 0.00–0.93). A 5-year backtest shows a typical error of ±187.6%, 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 →
20250.000.000.93
20260.000.000.93
20270.000.000.93
20280.000.000.93
20290.000.000.93

Routes In Peninsular Florida

Routes recording Royal 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 →
Vero BeachFLORIDA72018
ScottsmoorFLORIDA52024
Boca RatonFLORIDA41988
Merritt Island 2FLORIDA32014
San AntonioFLORIDA21991
Sugarloaf Key 2FLORIDA22018
Merritt IslFLORIDA22008
St AugustineFLORIDA12023
IndiantownFLORIDA12001
Plantation KFLORIDA12004
SebastianFLORIDA11991
ShawanoFLORIDA12001
Key LargoFLORIDA11990
AripekaFLORIDA12023
Indiantown 2FLORIDA12021
Card SoundFLORIDA12021
Sugarloaf KeyFLORIDA12004
Ridge HarborFLORIDA12017

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