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

Caspian Tern Population Trend in Utah

All statesWetland birds

Caspian Tern in Utah has risen sharply: up 57% on the route-weighted index since 1995.

+57%Since 1995TrendPercent 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 →
11Routes 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 →
23YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Caspian Tern Trends in UtahNotable 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 Caspian Tern in Utah. See the full index history below.

Caspian Tern Population Forecast in Utah

If the recent trend holds, Caspian Tern in Utah is projected to rise about 68% by 2028 — from 0.06 in 2023 to a central estimate of 0.10 (95% range 0.00–0.39). A 5-year backtest shows a typical error of ±472.6%, with 100% of held-out values landing inside the 95% band.

+68%Change by 2028TrendPercent 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 →
0.10Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.3995% 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 →
±472.6%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, Caspian Tern in Utah is projected to rise about 68% by 2028 — from 0.06 in 2023 to a central estimate of 0.10 (95% range 0.00–0.39). A 5-year backtest shows a typical error of ±472.6%, with 100% of held-out values landing inside the 95% band.19932028
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 →
20240.100.000.39
20250.100.000.39
20260.100.000.39
20270.100.000.39
20280.100.000.39

Caspian Tern Survey Routes in Utah

Routes recording Caspian Tern in Utah.
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 →
Callao420231995
Leamington220162016
Kamas220112011
Promontory120171998
Neponset Res120112000
Lost Cr. Res120112011
Saleratus Cr120092004
Hardware Ranch120092007
Delta119941994
Ferron120032003
Bear River120221993

Caspian Tern Population Trend in Other States

alabamaalaskacaliforniadelawarefloridaidahoillinoisindianalouisianamarylandmichiganminnesotamontananevadanorth-carolinanorth-dakotaoregonsouth-carolinatexasvermontvirginiawashingtonwisconsinwyoming

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