BirdAnalyst
Species · BCR 37 · BBS 2025 Release · 1966–2024

Least Tern In Gulf Coastal Prairie

All regionsGulf Coastal PrairieWetland birds

Least Tern in Gulf Coastal Prairie has edged up: up 14% on the route-weighted index since 1971.

+14%Since 1971TrendPercent 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 →
24Routes 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 →
47YearsYears 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 Least Tern in Gulf Coastal Prairie. See the full index history below.

Least Tern In Gulf Coastal Prairie Population Forecast

If the recent trend holds, Least Tern in Gulf Coastal Prairie is projected to rise about 55% by 2029 — from 0.81 in 2024 to a central estimate of 1.3 (95% range 0.00–3.8). A 5-year backtest shows a typical error of ±75.2%, with 100% of held-out values landing inside the 95% band.

+55%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 →
1.3Projected 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 →
0.00–3.895% 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 →
±75.2%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 Gulf Coastal Prairie is projected to rise about 55% by 2029 — from 0.81 in 2024 to a central estimate of 1.3 (95% range 0.00–3.8). A 5-year backtest shows a typical error of ±75.2%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20251.20.003.8
20261.20.003.8
20271.20.003.8
20281.20.003.8
20291.30.003.8

Routes In Gulf Coastal Prairie

Routes recording Least Tern in Gulf Coastal Prairie.
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 →
Oyster LakeTEXAS162024
Grand IsleLOUISIANA112019
Bayside 2TEXAS92004
JuniorLOUISIANA81988
Bayside 3TEXAS72016
L. Atascosa NwrTEXAS62023
Padre Island PaisTEXAS52015
StowellTEXAS42023
CreoleLOUISIANA31978
Loyola BeachTEXAS32008
Gran ChenierLOUISIANA21976
HackberryLOUISIANA22016
Sabine NwrLOUISIANA21996
Lag AtascosaTEXAS21985
IndianolaTEXAS22014
WinnieTEXAS21997
Loyola Beach 2TEXAS22021
LafitteLOUISIANA11989
Ltl ChenierLOUISIANA12024
Sabine Nwr 2LOUISIANA12015
DanburyTEXAS12009
ChinquapinTEXAS12006
BaysideTEXAS12010
Port AcresTEXAS12004

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