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

Royal Tern Population Trend in Texas

All statesWetland birds

Royal Tern in Texas has surged: up 249% on the route-weighted index since 1976.

+249%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 →
13Routes 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 Royal Tern Trends in TexasNotable 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 increasecomputed 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 surged in Texas: up 249% on the route-weighted index since 1976.

Royal Tern Population Forecast in Texas

If the recent trend holds, Royal Tern in Texas is projected to fall about 21% by 2029 — from 0.19 in 2024 to a central estimate of 0.15 (95% range 0.02–0.27). A 5-year backtest shows a typical error of ±56.2%, with 40% of held-out values landing inside the 95% band.

-21%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 →
0.15Projected 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 →
0.02–0.2795% 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 →
±56.2%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, Royal Tern in Texas is projected to fall about 21% by 2029 — from 0.19 in 2024 to a central estimate of 0.15 (95% range 0.02–0.27). A 5-year backtest shows a typical error of ±56.2%, with 40% of held-out values landing inside the 95% band.19712029
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 →
20250.140.010.26
20260.140.020.26
20270.140.020.27
20280.140.020.27
20290.150.020.27

Royal Tern Survey Routes in Texas

Routes recording Royal Tern in Texas.
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 →
Padre Island Pais4120152015
Bayside 31420242011
Oyster Lake1120241995
Vanderbilt519751975
Bayside320032003
L. Atascosa Nwr220172017
Indianola220241979
Chinquapin220241995
Stowell220221976
Lag Atascosa120121971
Kingsville119761976
Winnie119941994
Danbury120232012

Royal Tern Population Trend in Other States

alabamacaliforniadelawarefloridageorgialouisianamarylandnew-jerseynorth-carolinasouth-carolinavirginia

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