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Species · Kansas · BBS 2025 Release · 1966–2024

Forster's Tern Population Trend in Kansas

All statesWetland birds

Forster's Tern in Kansas has fallen sharply: down 58% on the route-weighted index since 1969.

-58%Since 1969TrendPercent 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 →
3Routes 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 →
34YearsYears 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 KansasNotable 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 Kansas: down 58% on the route-weighted index since 1969.

Forster's Tern Population Forecast in Kansas

If the recent trend holds, Forster's Tern in Kansas is projected to stay roughly flat through 2024, near 0.12 (95% range 0.00–0.66). A 5-year backtest shows a typical error of ±283.2%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2024TrendPercent 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 →
0.12Projected 2024 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.6695% 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 →
±283.2%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, Forster's Tern in Kansas is projected to stay roughly flat through 2024, near 0.12 (95% range 0.00–0.66). A 5-year backtest shows a typical error of ±283.2%, with 100% of held-out values landing inside the 95% band.19672024
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 →
20200.130.000.67
20210.130.000.66
20220.130.000.66
20230.130.000.66
20240.120.000.66

Forster's Tern Survey Routes in Kansas

Routes recording Forster's Tern in Kansas.
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 →
Logan1020012001
Albert120191967
Missler119891989

Forster's Tern Population Trend in Other States

alabamacaliforniacoloradodelawarefloridageorgiaidahoillinoisindianaiowalouisianamarylandmichiganminnesotamontananebraskanevadanew-jerseynew-yorknorth-carolinanorth-dakotaoregonsouth-carolinasouth-dakotatexasutahvirginiawashingtonwisconsinwyoming

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