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Species · Wyoming · BBS 2025 Release · 1966–2024

Forster's Tern Population Trend in Wyoming

All statesWetland birds

Forster's Tern in Wyoming has fallen sharply: down 63% on the route-weighted index since 1988.

-63%Since 1988TrendPercent 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 →
7Routes 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 →
20YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Forster's Tern Trends in WyomingNotable 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 →

Forster's Tern has fallen sharply in Wyoming: down 63% on the route-weighted index since 1988.

Forster's Tern Population Forecast in Wyoming

If the recent trend holds, Forster's Tern in Wyoming is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.06). A 5-year backtest shows a typical error of ±64.9%, with 80% of held-out values landing inside the 95% band.

n/aChange 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 →
0.01Projected 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 →
0.00–0.0695% 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 →
±64.9%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, Forster's Tern in Wyoming is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.06). A 5-year backtest shows a typical error of ±64.9%, with 80% of held-out values landing inside the 95% band.19832029
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 →
20250.010.000.06
20260.010.000.06
20270.010.000.06
20280.010.000.06
20290.010.000.06

Forster's Tern Survey Routes in Wyoming

Routes recording Forster's Tern in Wyoming.
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 →
Midvale619961996
Alpine219991999
Kaycee120242024
Seedskadee120142014
Nowood120002000
Harmony120231987
Fontenelle120171983

Forster's Tern Population Trend in Other States

alabamacaliforniacoloradodelawarefloridageorgiaidahoillinoisindianaiowakansaslouisianamarylandmichiganminnesotamontananebraskanevadanew-jerseynew-yorknorth-carolinanorth-dakotaoregonsouth-carolinasouth-dakotatexasutahvirginiawashingtonwisconsin

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